Show the walk's path on the line below its display (closes #160 )

On a terminal, each draw of the walk shows the path of the last file it found on the line below, cut short before the last column with wide characters counted as two columns. The progressbar library's detail row draws it. Control characters in the path are written out, as \t or \x1b, so that the terminal does not act on them. The line is erased before a warning and when the walk ends, so the next phase is drawn on it. Nothing changes when stderr is not a terminal. github.com/rivo/uniseg, already in the module graph through the progressbar library, becomes a direct dependency for the column count. Model: opus-5-5
TODO.md: keep only open work (closes #167 ) (#180 )
2026-11-11 08:22:51 +00:00 · 2026-11-11 09:07:13 +01:00 · 2026-11-11 08:37:18 +01:00 · 2026-11-11 07:22:28 +01:00
17 changed files with 746 additions and 1154 deletions
@@ -22,14 +22,14 @@ records the files it finds in an SQLite database. SQLite keeps a whole database
 in one file. The database is kept between runs. A rescan reads only new and
 changed files. That makes `scan` cheap enough to run every day from `cron`, the
 system's job scheduler. `report`, `trees` and `info` work from the database and
-can run at any time. `report` and `trees` leave out a copy that was deleted
+can run at any time. `dwim` scans `/` and then prints the `trees` report, for a
-after the scan. `dwim` scans `/` and then prints the `trees` report, for a first
+first look at a new machine with one command.
 look at a new machine with one command.
 ## Getting Started
 ```sh
 make build
 export SFDUPES_DATABASE="$HOME/.local/share/sfdupes/db.sqlite"
 ./sfdupes scan /srv
 ./sfdupes report > dupes.tsv
 ./sfdupes trees > dupetrees.tsv
@@ -45,10 +45,8 @@ that stands for a piece of hardware, such as a disk or a terminal. `report`
 prints the file-level duplicates. `trees` prints the duplicate directory trees.
 `info` prints the database's path, size and record count.
-Root keeps the database in `/var/lib/sfdupes/db.sqlite`. Any other user keeps it
+The database is `/var/lib/sfdupes/db.sqlite` unless `SFDUPES_DATABASE` names
-in `sfdupes/db.sqlite` in the XDG state directory, `~/.local/state` by default
+another file. The first `scan` creates it.
 on Linux. `SFDUPES_DATABASE` names another file (see "Location"). The first
 `scan` creates the database.
 `report`, `trees` and `info` write their data to stdout. Progress, warnings and
 errors go to stderr. stdout and stderr are a program's two output streams. The
@@ -150,9 +148,8 @@ walk"). As the file `/etc/cron.d/sfdupes`:
 - `report`, `trees` and `info` need only read access to the database. The umask
  is the setting that removes permissions from the files a process creates.
  Under the usual umask of `022`, the first scan creates the database readable
-  by every user. Another user can then run those three commands against root's
+  by every user. An unprivileged user can then run those three commands against
-  database, with `SFDUPES_DATABASE=/var/lib/sfdupes/db.sqlite` before the
+  root's database.
  command.
 ### Reading the reports
@@ -257,15 +254,14 @@ In order:
 - `report` prints the file-level duplicate report from the database.
 - `trees` prints the duplicate-tree report from the database.
 - `info` prints the database's details.
- `dwim` scans `/` with the default excludes, then prints the duplicate-tree
+- `dwim` scans `/`, then prints the duplicate-tree report.
  report.
 ```
 sfdupes scan [--workers N] [-x] [--no-default-excludes] [--exclude PATH]... PATH...
 sfdupes report > dupes.tsv
 sfdupes trees > dupetrees.tsv
 sfdupes info
-sfdupes dwim
+sfdupes dwim [--workers N] [-x] [--no-default-excludes] [--exclude PATH]...
 sfdupes --version
 sfdupes [command] --help
 ```
@@ -292,23 +288,23 @@ The reference below is also the program's specification.
 ### Settings
 - `SFDUPES_DATABASE` names the database file. When it is unset or empty, the
-  database is at its default path (see "Location"). There is no command-line
+  database is `/var/lib/sfdupes/db.sqlite`. There is no command-line flag for
-  flag for it. The path names the file exactly, whatever characters it holds. A
+  it. The path names the file exactly, whatever characters it holds. A relative
-  relative path is relative to the working directory.
+  path is relative to the working directory.
- `--workers N` (`scan`) sets how many directories `scan` reads at once while it
+- `--workers N` (`scan`, `dwim`) sets how many directories `scan` reads at once
-  lists the trees. It also sets how many files `scan` reads at once while it
+  while it lists the trees. It also sets how many files `scan` reads at once
-  hashes them. The default is the number of CPUs. `N` must be at least 1. A
+  while it hashes them. The default is the number of CPUs. `N` must be at
-  smaller value is a usage error, reported in one line on stderr with exit 2
+  least 1. A smaller value is a usage error, reported in one line on stderr with
-  before anything is scanned.
+  exit 2 before anything is scanned.
- `-x`, `--one-file-system` (`scan`) keeps the walk of each operand out of
+- `-x`, `--one-file-system` (`scan`, `dwim`) keeps the walk of each operand out
-  directories on other filesystems, as the same flag does for `du` and `rsync`.
+  of directories on other filesystems, as the same flag does for `du` and
-  By default the walk also enters directories on other filesystems.
+  `rsync`. By default the walk also enters directories on other filesystems.
- `--no-default-excludes` (`scan`) lets the walk enter the default excludes.
+- `--no-default-excludes` (`scan`, `dwim`) lets the walk enter the default
-  Those are the system and temporary directories the walk otherwise leaves out,
+  excludes. Those are the system and temporary directories the walk otherwise
-  such as `/var/tmp` on Linux (see "Rules for the walk").
+  leaves out, such as `/var/tmp` on Linux (see "Rules for the walk").
- `--exclude PATH` (`scan`) keeps the walk out of `PATH` and everything below
+- `--exclude PATH` (`scan`, `dwim`) keeps the walk out of `PATH` and everything
-  it. `PATH` may be a directory or a file. The flag may be given more than once.
+  below it. `PATH` may be a directory or a file. The flag may be given more than
-  The walk knows `PATH` by its device ID and inode number, as it knows the
+  once. The walk knows `PATH` by its device ID and inode number, as it knows the
  database files (see "Rules for the walk"). So the walk leaves `PATH` out
  whatever path leads to it. That includes a hard link to a file given as
  `PATH`. A symlink given as `PATH` excludes its target. An empty `PATH`, as in
@@ -319,8 +315,10 @@ The reference below is also the program's specification.
 - `--version`, `-v` prints `sfdupes VERSION` (see "Install") to stdout and
  exits 0. It writes nothing to stderr.
 - `--help`, `-h`, alone or after a subcommand, prints the help text to stderr
-  and exits 0. It writes nothing to stdout. `sfdupes scan --help` also lists the
+  and exits 0. It writes nothing to stdout. The help of `sfdupes` and of `scan`
-  default excludes of the system it runs on, and the filesystem types the walk
+  names the database. The help of `report`, `trees`, `info` and `dwim` says what
  each prints. `sfdupes scan --help` and `sfdupes dwim --help` also list the
  default excludes of the system they run on, and the filesystem types the walk
  never records anything on.
 ### Duplicate detection
@@ -859,14 +857,25 @@ trees: 14 records read, 1 duplicate tree groups, 1 dupe trees, 3.0 KiB reclaimab
 ### `dwim` mode
 `dwim`, short for "do what I mean", scans a new machine and reports its
-duplicate trees in one command. It takes no positional arguments and no flags of
+duplicate trees in one command. It takes no positional arguments. Like `scan`,
-its own. Like `scan`, it should run as root, so that it can read every file.
+it should run as root, so that it can read every file.
-`dwim` runs what `sfdupes scan /` runs with no flags. The walk skips the default
+`dwim` takes these flags of `scan`, with the same meaning (see "Settings"):
-excludes and crosses into other filesystems. `--workers` keeps its default. The
+
 - `--workers N`;
 - `-x`, `--one-file-system`;
 - `--no-default-excludes`;
 - `--exclude PATH`, which may be given more than once.
 `dwim` runs what `sfdupes scan /` runs with the same flags. With no flags, the
 walk skips the default excludes and crosses into other filesystems. The
 database, its creation and the scan lock are those of `scan`. Then `dwim` runs
 what `sfdupes trees` runs. The largest trees come first.
 ```
 sfdupes dwim -x --exclude /srv/cache
 ```
 The report goes to stdout, exactly as `trees` prints it. On stderr comes what
 `scan` prints, then what `trees` prints, then one last line:
@@ -928,22 +937,7 @@ All five subcommands work on one SQLite database file.
 #### Location
 The database is the file named by `SFDUPES_DATABASE`, when that is set and not
-empty. Otherwise it is at its default path, which depends on the user:
+empty, and otherwise `/var/lib/sfdupes/db.sqlite`.
 - For root, it is `/var/lib/sfdupes/db.sqlite`.
 - For any other user, it is `sfdupes/db.sqlite` in the XDG state directory. That
  directory is `$XDG_STATE_HOME` when that is set and not empty. Otherwise it is
  `~/.local/state` on Linux and `~/Library/Application Support` on macOS. An
  `XDG_STATE_HOME` that is not an absolute path is a fatal error, exit 1, for
  every subcommand. The error names `XDG_STATE_HOME`.
 `scan` creates each missing directory on the way to the database with mode 755.
 At the default path of a user other than root, it uses mode 700 instead, as the
 XDG Base Directory specification asks. Other users cannot enter a directory with
 mode 700, so they cannot read a database in it.
 All five subcommands use the same default, so a user's `report` reads the
 database that user's `scan` wrote.
 Each subcommand prints one line on stderr naming the database it uses, before
 anything else and whether or not stderr is a terminal. The line gives the path
@@ -983,9 +977,9 @@ Only one `scan` at a time can hold the lock.
 - For its whole run, `scan` holds a lock on a lock file beside the database. The
  lock is taken with the `flock(2)` system call, a request a program makes to
  the kernel, and only one process can hold it. The lock file's name is the
-  database's path, with symlinks resolved, plus `.lock`. For root, by default,
+  database's path, with symlinks resolved, plus `.lock`. By default that is
-  that is `/var/lib/sfdupes/db.sqlite.lock`. A path through a symlink names the
+  `/var/lib/sfdupes/db.sqlite.lock`. A path through a symlink names the same
-  same lock file.
+  lock file.
 - `scan` takes the lock before it walks the filesystem or opens the database.
  Just before that, it creates the database file, empty, if it is missing. So
  the lock file is named the same way before the first scan as after. A symlink
@@ -1207,6 +1201,14 @@ On a terminal:
    ⠹ [3/4] hash: [12345/98765], 92 files/s, elapsed 2m32s, remain 17m44s            12% |█         |
    ```
 - During `scan`'s `walk`, the line below the display shows the path of the last
  file the walk found. Each draw shows the path of that moment, cut short before
  the terminal's last column. The path is escaped as in the reports (see "Report
  output format"). Each control character left after that is written as `\x` and
  its code in two hexadecimal digits, such as `\x1b` for the escape character. A
  control character is one that a terminal acts on instead of showing. The line
  is erased when the walk ends, and the next phase is drawn on it.
 - No line reaches the terminal's last column. A line too wide for the terminal
  first leaves out its rate, the words of a stalled phase, or what the phase is
  waiting for. It leaves out its bar next. It is cut short at the edge only when
@@ -4,7 +4,7 @@
  the tracker yet is filed as an issue first.
 - Branch from `next`.
 - Do the work, with tests, in small focused commits.
- Record the step at the top of Completed Steps, in the same commit as the work.
+- Delete Next Step from `TODO.md`, in the same commit as the work.
 - Push the branch and open a PR against `next`. Its title ends with
  ` (closes #N)`.
 - An independent review gates each merge to `next`. Every finding is addressed
@@ -15,8 +15,7 @@
 - Pre-1.0.
 - The tracker is authoritative for the pre-1.0 backlog. The open issues under
-  the `1.0.0` milestone are what remains before the tag. This file records
+  the `1.0.0` milestone are what remains before the tag.
  history and process, not the queue.
 # Next Step
@@ -24,767 +23,6 @@
  https://git.eeqj.de/sneak/sfdupes/milestone/17. The issues are not restated
  here, because a copy drifts as soon as the tracker moves.
 # Completed Steps
 Newest first. An entry ends with its date and its issue or branch, where those
 are known.
 - Without `SFDUPES_DATABASE`, a user other than root keeps the database in
  `sfdupes/db.sqlite` under the XDG state directory, `~/.local/state` by
  default. Root keeps `/var/lib/sfdupes/db.sqlite`. `sfdupes --help` says where
  the database is (2026-11-11, https://git.eeqj.de/sneak/sfdupes/issues/171)
 - New `scan` flag `--exclude PATH`, which may be repeated. The walk neither
  enters nor records an excluded path, and keeps the records below it. An
  operand at or below one is a fatal error (2026-11-11,
  https://git.eeqj.de/sneak/sfdupes/issues/163)
 - `report` and `trees` leave out a copy that was deleted after the scan. Each
  checks only the copy itself with `lstat`: the file, or the directory at the
  top of a tree. A group left with one copy is not reported. A missing `scan`
  operand is still a fatal error (2026-11-11,
  https://git.eeqj.de/sneak/sfdupes/issues/173)
 - The usage line of `scan` no longer ends in `[flags]`. It is the line
  `README.md` shows under "Subcommands" (2026-11-11,
  https://git.eeqj.de/sneak/sfdupes/issues/169)
 - `report` and `trees` leave out empty files. `report` writes no group of size
  0, and `trees` writes no group whose trees hold 0 bytes. An empty file still
  counts toward a tree's digest (2026-11-11,
  https://git.eeqj.de/sneak/sfdupes/issues/178)
 - The Go code moved out of the repository root. `cmd/sfdupes/main.go` is the
  command, and it calls `Main` in the package `internal/sfdupes`. `main.go`
  became `internal/sfdupes/cli.go`. Every other file kept its name. The install
  path is now `sneak.berlin/go/sfdupes/cmd/sfdupes` (2026-11-10,
  https://git.eeqj.de/sneak/sfdupes/issues/157)
 - New subcommand `dwim`. It runs what `sfdupes scan /` runs with no flags, then
  what `sfdupes trees` runs. Its last line on stderr says that `sfdupes trees`
  prints the report again (2026-11-06,
  https://git.eeqj.de/sneak/sfdupes/issues/154)
 - `scan` resolves each operand to its real path, symlinks followed, before the
  walk. A symlink operand is scanned at its target instead of skipped. With
  `/srv/link` a symlink to a directory outside `/srv`, `scan /srv /srv/link/sub`
  walks `sub` on its own instead of dropping it and deleting its records
  (2026-11-06, https://git.eeqj.de/sneak/sfdupes/issues/144)
 - `README.md` and a comment in `internal/sfdupes/scan.go` no longer say ZFS
  counts a new file's blocks only seconds after the write. The count can land in
  under a second. Both now say up to seconds after the write, as the comment on
  `diskSizeOf` in `internal/sfdupes/scan_test.go` does (2026-11-03,
  https://git.eeqj.de/sneak/sfdupes/issues/152)
 - The three disk size tests in `internal/sfdupes/scan_test.go` no longer fail at
  random on ZFS. `unix.Sync` can return before ZFS has counted a file's blocks,
  and one ZFS commit can take a file through several sizes. The test that needs
  the size to change waits for it, for at most 30 seconds. Each test reads the
  size before and after its scan. The rewrite test rescans until the two reads
  match, then compares exactly. The other two fail only on a `disk_size` outside
  the two reads (2026-11-02, https://git.eeqj.de/sneak/sfdupes/issues/150)
 - `TODO.md` rewritten from scratch by the same rules as `README.md`, sentence by
  sentence. Every completed step is kept, with its date and its issue or branch.
  The policy-compliance checklist of 2026-07-22 is folded into its step
  (2026-11-02, https://git.eeqj.de/sneak/sfdupes/issues/135)
 - `README.md` rewritten from scratch, sentence by sentence, as a newcomer reads
  it. It leads with what the program is and how to use it. A reference section
  covers every setting and every subcommand. Development and testing come last.
  Every statement was checked against the code on `next`. Five comments in
  `internal/sfdupes/cli_test.go` cite "Settings", where their rules now live.
  One comment each in these files cites what the README now says:
    - `internal/sfdupes/scan_test.go`;
    - `internal/sfdupes/trees_test.go`;
    - `internal/sfdupes/exclude_test.go`.
    (2026-11-02, https://git.eeqj.de/sneak/sfdupes/issues/135)
 - Each record holds `disk_size`, the bytes the file takes on disk. That is its
  allocated blocks, `st_blocks` × 512, from the `lstat` call the walk already
  makes. `trees` prints a `disk_size` column after `size`. It is the sum over
  the `dupe` copy's files. On a compressed or sparse file `disk_size` differs
  from `size`. A rescan updates the `disk_size` of an unchanged file whose size
  on disk changed, without reading the file (2026-10-27,
  https://git.eeqj.de/sneak/sfdupes/issues/147)
 - The database keeps the number of records and the sum of their sizes in the one
  row of a `totals` table. Three triggers on `files` keep that row current.
  `info` reads that row. So do `scan`'s `load` phase and the `read` phases of
  `report` and `trees`, for their totals. No count reads every record any more.
  The triggers make each write to `files` slower. `scan` keeps SQLite's
  temporary data in memory. That wins back part of that time (2026-10-27,
  https://git.eeqj.de/sneak/sfdupes/issues/146)
 - an operand at or inside a directory named `.zfs` is never scanned, whether
  given alone or under another operand. `scan` warns about it, counts it as
  skipped and does not walk it (2026-10-26,
  https://git.eeqj.de/sneak/sfdupes/issues/142)
 - A file or directory removed while the scan runs is not an error, in the walk
  or in the hash phase. The scan prints no line for it and does not count it as
  skipped. When the first of several hard links to a file is gone, the hash
  phase reads the next one instead. On a terminal every progress display starts
  with the spinner, the hash phase's included. A phase with an exact total ends
  its line with its percent and a 10-column bar at the terminal's right edge.
  The bar no longer moves as the line's length changes. A line too wide for the
  terminal now loses its rate before its bar. The time remaining is labelled
  `remain`, not `eta` (2026-10-26, https://git.eeqj.de/sneak/sfdupes/issues/133)
 - The `head`, `tail` and `content` columns are BLOBs, each holding the raw 32
  bytes of a SHA-256. That is half the size of the hex text they held. The
  hashes stay raw from the hash phase through the database to `report` and
  `trees`. Reading a record whose hash is not 32 bytes is an error (2026-10-26,
  https://git.eeqj.de/sneak/sfdupes/issues/134)
 - The hash phase gives three hashes to every file that the walk records. `head`
  and `tail` are the SHA-256 of its first and last 64 KiB. `content` is the
  SHA-256 of the whole file under 100 MiB, and of 1 MiB at each gigabyte from
  100 MiB up. Gone are:
    - the 10 MiB and 50 MiB thresholds;
    - the size census, which counted the sizes of every walked file and of every
      record outside the operands. A file was hashed only when the census showed
      another file of its size;
    - the records without hashes;
    - the content phase.
    A scan has four phases, and a rescan reads only new and changed files.
    `info` no longer counts the records with `head` and `tail` hashes, nor those
    with a content hash, since every record has all three (2026-10-25,
    https://git.eeqj.de/sneak/sfdupes/issues/132)
 - `REPO_POLICIES.md` and the four scripts that pass `CACHEBUST` were copied
  again from `sneak/prompts` `next` at `0653579`. Two steps now come before
  `ARG CACHEBUST`:
    - the module download in the `lint`, `test` and `builder` stages of the
      `Dockerfile`;
    - the package install in `builder`.
    Docker keeps them until one of these changes:
    - the base image;
    - the install line;
    - `go.mod` or `go.sum`.
    Every step that checks or compiles the code still comes after
    `ARG CACHEBUST`. `golangci-lint run` also keeps the linter's own cache.
    README says the same (2026-10-18,
    https://git.eeqj.de/sneak/sfdupes/issues/109)
 - The release rule was set. Until 1.0, each tip of `main` that passes the build
  gets the next `v0.0.N` tag.
  `go install sneak.berlin/go/sfdupes/cmd/sfdupes@latest` then installs it.
  `go.mod` retracts `v0.0.1`, the early build without a database. When the
  linker set no version, `sfdupes --version` prints the version Go recorded in
  the binary. That is the tag, or the pseudo-version of a `go install` build. It
  prints `dev` only when neither is known. README "Install" documented:
    - the rule;
    - what `@main` and `v0.0.1` give;
    - how to check an installed binary.
    (2026-10-17, https://git.eeqj.de/sneak/sfdupes/issues/116)
 - `scan` creates the database's directory where the database path leads. The
  directory is the path with its last element cut off as text, so a `..` in it
  stays. A `..` after a symlinked directory therefore goes through the symlink,
  as it does when the file is opened. With
  `SFDUPES_DATABASE=/srv/link/../new/db.sqlite` and `/srv/link` a symlink to
  `/data/x`, it now creates `/data/new` and the database in it. It used to
  create `/srv/new` and then fail (2026-10-17,
  https://git.eeqj.de/sneak/sfdupes/issues/119)
 - `scan` never records its own database. Once the database and its `.lock` file
  are open, it notes the device and inode of each of these:
    - the database file;
    - its `-wal` and `-shm` files;
    - the `.lock` file.
    The walk passes over any file with the device and inode of one of them,
    however it reaches the file. It prints no line for such a file and counts
    nothing. A record an earlier scan left for one of them is deleted
    (2026-10-17, https://git.eeqj.de/sneak/sfdupes/issues/115)
 - `scan` never records or reads anything on a filesystem that is not persistent,
  such as `tmpfs` or `proc`. Such a filesystem is one the kernel makes up or
  keeps in memory. `scan` matches them by device ID, however the walk or the
  content phase reaches a path. As the scan starts, it lists the mounted
  filesystems of those types, from `/proc/self/mountinfo` on Linux and from the
  mount list on macOS. No flag turns that off. Below an operand, the walk does
  not enter the default excludes either. So `sfdupes scan /` skips the kernel's
  view of the running system and the temporary directories. On Linux those are:
    ```
    /proc, /sys, /dev, /run, /tmp, /var/tmp
    ```
    On macOS they are:
    ```
    /dev, /private/tmp, /private/var/tmp, /private/var/vm
    /System/Volumes/VM, /System/Volumes/Data
    ```
    A Windows list exists in the code but is not used. An operand at or inside a
    default exclude is still walked. The scan prints a line for each path it
    leaves out, without counting it as skipped. The records there count as
    outside the scanned operands, as for `-x`. `--no-default-excludes` turns off
    the default excludes only, and `scan --help` lists them (2026-10-17,
    https://git.eeqj.de/sneak/sfdupes/issues/124)
 - A progress display's rate covers the items completed over the last 5 seconds.
  When stderr is not a terminal, it covers the items since the line before. It
  falls to 0 while nothing completes. A burst after a wait no longer reads as a
  steady rate of over 1,000 files a second. The time remaining still comes from
  the phase's average. Once no item has completed for 10 seconds, the line shows
  `stalled` and where the phase waits in place of the rate, as
  `stalled disk/db`. The places are:
    - `disk`;
    - `db`;
    - `out`, for stdout;
    - `cpu`.
    A phase that may wait in two places names both. Each phase's word is set in
    the code that defines the phase. A line too wide for the terminal loses its
    bar first, then its rate or those words. Four parts stay whole:
    - the phase;
    - the progress;
    - the elapsed time;
    - the ETA, the time remaining.
    The content phase had one display for its checks and one for its reads. Both
    lost those words on an 80-column terminal, at counts like those of README's
    example. That happened for most elapsed times and ETAs in minutes. Every
    other phase kept them whenever the elapsed time and the ETA were both in
    minutes. The content phase writes its last partial batch, the records not
    yet written, under a display of its own (2026-10-16,
    https://git.eeqj.de/sneak/sfdupes/issues/125)
 - New subcommand `info` prints the database's details on stdout, one per line as
  a name, a tab and the value:
    - the path and where it came from;
    - the sizes of the database file and of its `-wal` file, when there is one;
    - when the database file was last changed;
    - the schema version;
    - the number of records;
    - how many records have `head` and `tail` hashes;
    - how many records have a content hash;
    - the sizes of all records added up.
    It opens the database as `report` does and shows two phases on stderr,
    `[1/2] open` and `[2/2] count`. The schema version and the counts come from
    one read-only transaction, a read of the database at one moment. The counts
    come from one query (2026-10-16,
    https://git.eeqj.de/sneak/sfdupes/issues/117)
 - `report` shows its work on stderr in two phases, `[1/2] open` and
  `[2/2] read`, with the progress display `scan` and `trees` use. The display
  runs from the moment `report` starts until the summary line. `open` says it is
  opening the database, also while it waits on a busy one. `read` counts the
  records, then reads them against that count in signature order. SQLite takes
  that order from the `files_signature` index without sorting, so the first
  record comes at once. `report` forms the duplicate groups itself and holds
  only those of the size it is reading. It writes them ordered by first path
  before it reads the next size. stdout and the summary line are unchanged, and
  SQLite no longer needs a temporary file to sort in (2026-10-16,
  https://git.eeqj.de/sneak/sfdupes/issues/114)
 - `trees` shows its work on stderr in four phases, from `[1/4] open` to
  `[4/4] write`, each with the progress display `scan` uses. The display runs
  from the moment `trees` starts until the summary line. `open` says it is
  opening the database, also while it waits on a busy one. `read` counts the
  records, then reads them against that count. `group` counts the directories it
  groups, and `write` the groups it writes. A display's rate names what its
  phase counts:
    - files;
    - records;
    - directories;
    - groups.
    stdout and the summary line are unchanged. When stdout and stderr are the
    same file, as one terminal is, no line of stdout shares a line with the
    display. When they are not, the display keeps being drawn while stdout waits
    on a slow reader (2026-10-16, https://git.eeqj.de/sneak/sfdupes/issues/113)
 - Each `scan` phase's progress display names the phase and its place among the
  five, as `[2/5] walk`. It runs from the moment that the phase starts. It
  shows:
    - the progress;
    - the elapsed time;
    - the ETA, the time remaining.
    `load` counts the records first. The walk's total is estimated from the
    records under the operands. The content phase takes its total from SQLite's
    grouping alone. Until the first record is returned, it says it is searching
    the database. On a terminal a phase with an exact total draws its line
    followed by the bar of the progress-bar library. Any other phase draws a
    spinner followed by the line. Every display is drawn again several times a
    second. No line reaches the terminal's last column, however narrow the
    terminal is, even after it is made narrower during a phase. A line too wide
    leaves out its rate, then its bar. The rest stays whole. The line is cut
    short only when the rest alone does not fit, as below about 70 columns late
    in a large scan. When stderr is not a terminal, the line is printed every 5
    seconds whether or not an item completed (2026-10-16,
    https://git.eeqj.de/sneak/sfdupes/issues/112)
 - `scan`, `report` and `trees` first print a line on stderr naming the database
  they use, as an absolute path. The line says whether that path is the default
  or comes from `SFDUPES_DATABASE`. `scan` says when the database is new. README
  "Database" says when `scan` writes each file (2026-10-16,
  https://git.eeqj.de/sneak/sfdupes/issues/111)
 - The canonical files and model scripts were copied again from `sneak/prompts`
  `next` at `e3f79c4`:
    - `golangci-lint` v2.14.0;
    - lint and test are phases of the `Dockerfile` that write no image, and
      `make test` runs the suite under the race detector. Gone are
      `Dockerfile.lint`, `script/verify-lint-image-pin` and `make test-race`;
    - every `docker build` in `script/` passes a new `CACHEBUST` value. Every
      stage of the `Dockerfile` declares it first, so every `RUN` step runs on
      every build. The steps that compile keep Go's build cache, and the tests
      run with `-count=1`;
    - `prettier` runs on the host, from the `node` and `yarn` that
      `script/bootstrap` installs. The `prettier` and `markdown` stages are
      gone, and the build stage installs `git` and `make` itself;
    - a new push cancels the workflow's older run on the same branch, and a run
      stops after 20 minutes;
    - a coding agent's settings file is deleted.
    Since https://git.eeqj.de/sneak/sfdupes/issues/109 two steps come before
    `ARG CACHEBUST`:
    - the module download in `lint`, `test` and the build stage;
    - the install of `git` and `make` in the build stage.
    Docker keeps them between builds. Every step that checks or compiles the
    code still runs on every build (2026-10-15,
    https://git.eeqj.de/sneak/sfdupes/issues/95)
 - With `-x`, an operand under another operand is no longer dropped when a
  directory between the two, the inner one included, is on a different
  filesystem than the outer one. The inner operand is then walked on its own.
  For a regular-file operand the check starts at its directory. The records of
  files gone from below it are deleted (2026-10-14,
  https://git.eeqj.de/sneak/sfdupes/issues/106)
 - With `-x`, `scan` keeps the records below a directory on another filesystem
  under its operand, instead of deleting them. It counts their sizes in the size
  census (2026-10-14, https://git.eeqj.de/sneak/sfdupes/issues/99)
 - The hash and content phases open each file without blocking and check that it
  is still a regular file. A file that is now a FIFO or device node is warned
  about and skipped instead of hanging the scan (2026-10-14,
  https://git.eeqj.de/sneak/sfdupes/issues/100)
 - The scan lock file is named from the database's path with symlinks resolved,
  after `scan` creates the database file if it is missing. A scan through a
  symlink to the database therefore fails while another scan holds the lock
  (2026-10-14, https://git.eeqj.de/sneak/sfdupes/issues/101)
 - On a terminal, a warning for the last file of a phase no longer erases the
  phase's finished bar. The bar is drawn again below the warning (2026-10-14,
  https://git.eeqj.de/sneak/sfdupes/issues/102)
 - `scan` records the mtime to the nanosecond, as whole seconds in `mtime` plus
  `mtime_nsec`, and compares it at that resolution. A same-size rewrite within
  the same second is hashed again (2026-10-07,
  https://git.eeqj.de/sneak/sfdupes/issues/12)
 - The narration was cut from `TODO.md` Completed Steps and from the comments in
  `script/`, `Dockerfile` and `Dockerfile.lint` (gone since
  https://git.eeqj.de/sneak/sfdupes/issues/95). The Workflow section now
  branches from and merges to `next` (2026-10-04,
  https://git.eeqj.de/sneak/sfdupes/issues/49)
 - `make test-race` ran the test suite under the race detector in a cgo-enabled
  container, outside `make check`. Since
  https://git.eeqj.de/sneak/sfdupes/issues/95 `make test` itself runs the suite
  under the race detector, in the `Dockerfile`'s Debian-based `test` phase.
  `make test-race` is gone (2026-10-04,
  https://git.eeqj.de/sneak/sfdupes/issues/18)
 - A bare `docker build .` failed, naming `script/cibuild` and `script/docker`,
  rather than serve the gates, the lint and test steps, from cache. Since
  https://git.eeqj.de/sneak/sfdupes/issues/95 a bare build succeeds, as
  `REPO_POLICIES.md` requires, and may serve the gates from cache. The builds in
  `script/` pass a new `CACHEBUST` value, so theirs always run (2026-10-04,
  https://git.eeqj.de/sneak/sfdupes/issues/39)
 - `make fmt` and `make fmt-check` run `prettier` over all Markdown, and the
  Gitea workflow checks it. All Markdown was reformatted (2026-10-04,
  https://git.eeqj.de/sneak/sfdupes/issues/19)
 - `script/lint` writes no image, so a run no longer leaves an untagged one
  behind (2026-10-04, https://git.eeqj.de/sneak/sfdupes/issues/48)
 - Tests cover:
    - a missing database;
    - `scan` keeping stdout empty;
    - its skip warning;
    - the `report` and `trees` summary lines;
    - every subcommand going through `runE`.
    (2026-10-04, https://git.eeqj.de/sneak/sfdupes/issues/16)
 - `.golangci.yml` was replaced with the current canonical copy, which uses
  `gomodguard_v2`, so lint no longer prints a deprecation warning (2026-10-04,
  https://git.eeqj.de/sneak/sfdupes/issues/26)
 - A test fails when either `hashWorker` cancellation check in
  `internal/sfdupes/scan.go` is removed (2026-10-04,
  https://git.eeqj.de/sneak/sfdupes/issues/83)
 - A database path holding `?`, `#` or `%` opens exactly the file it names
  (2026-10-04, https://git.eeqj.de/sneak/sfdupes/issues/55)
 - `scan` rejects `--workers` below 1 as a usage error instead of running
  single-threaded (2026-10-04, https://git.eeqj.de/sneak/sfdupes/issues/10)
 - A test fails when either walk cancellation check in `internal/sfdupes/scan.go`
  is removed (2026-10-04, https://git.eeqj.de/sneak/sfdupes/issues/81)
 - A test checks that `scan` refuses a database with another schema version
  (2026-10-04, https://git.eeqj.de/sneak/sfdupes/issues/64)
 - Four inaccurate comments in `internal/sfdupes/cancel_test.go` were corrected,
  and `walkCancelInFlightDirs` was renamed to `walkCancelInFlightFiles`
  (2026-10-04, https://git.eeqj.de/sneak/sfdupes/issues/33)
 - The `-x` filesystem-boundary rules in `subdirJob` are tested (2026-10-04,
  https://git.eeqj.de/sneak/sfdupes/issues/17)
 - `scan` creates the schema in one transaction. A version-0 database with a
  `files` table is refused with a clear schema-version error (2026-10-04,
  https://git.eeqj.de/sneak/sfdupes/issues/11)
 - README documents install, Docker, a daily `cron` scan and how to read and
  check the reports (2026-10-04, https://git.eeqj.de/sneak/sfdupes/issues/54)
 - The `Dockerfile` build stage kept the Go module cache out of `builder`'s home
  and copied the sources with `--chown`, so no `chown -R` walked them. Since
  https://git.eeqj.de/sneak/sfdupes/issues/95 there is no `builder` user and
  nothing changes owner. The build stage only compiles, as root, and the tests
  run as `nobody` in the `test` phase (2026-10-04,
  https://git.eeqj.de/sneak/sfdupes/issues/43)
 - `--version` prints `sfdupes VERSION` to stdout. README documents it and
  `--help` (2026-10-04, https://git.eeqj.de/sneak/sfdupes/issues/15)
 - `scan` stops cleanly on `SIGINT` or `SIGTERM`: it commits what it has hashed,
  deletes nothing more, and exits 1 (2026-10-04,
  https://git.eeqj.de/sneak/sfdupes/issues/5)
 - `report` and `trees` stream the records instead of holding them all in memory.
  The schema gains the `files_signature` index (2026-10-04,
  https://git.eeqj.de/sneak/sfdupes/issues/14)
 - Progress prints at once on a non-terminal and uses a real terminal test.
  Warnings print through a spinner instead of racing its redraw (2026-10-03,
  https://git.eeqj.de/sneak/sfdupes/issues/13)
 - These operands are warned about and skipped, and the records beneath them are
  kept:
    - symlinks;
    - sockets;
    - FIFOs;
    - device nodes;
    - `.zfs` directories.
    (2026-10-03, https://git.eeqj.de/sneak/sfdupes/issues/9)
 - `scan` holds a lock on a lock file beside the database for its whole run, so a
  second `scan` fails at once with exit 1 (2026-10-03,
  https://git.eeqj.de/sneak/sfdupes/issues/53)
 - Tests cover stdout write failures in `report` and `trees`. README states that
  `| head` ends `sfdupes` by `SIGPIPE` and that `>&-` writes to `/dev/null`
  (2026-10-03, https://git.eeqj.de/sneak/sfdupes/issues/30)
 - `report` and `trees` open the database read-only, and `scan` leaves it out of
  WAL mode, so reading needs only read access (2026-10-03,
  https://git.eeqj.de/sneak/sfdupes/issues/8)
 - Four characters are escaped in `report`, `trees` and warning paths:
    - tab;
    - newline;
    - carriage return;
    - backslash.
    The root directory's path is `/` (2026-10-03,
    https://git.eeqj.de/sneak/sfdupes/issues/7)
 - A plain `docker build .` stamps the `git` tag or short commit instead of
  `dev`. `.dockerignore` sends `.git` without `.git/config`. The build stage
  stamps the `VERSION` build argument, else `git describe --tags --always`. It
  fails if the context carries `.git` and the version is still empty, `dev` or
  `unknown`. The Gitea workflow checks out the full history (`fetch-depth: 0`),
  so it stamps the same value as `make build` (2026-10-02, branch `next`,
  https://git.eeqj.de/sneak/sfdupes/issues/67)
 - The 1 KiB end-window sampling was replaced with the hashes chosen by file
  size, and README "Duplicate detection" documented every size threshold. A file
  under 10 MiB was hashed in full, and its `head`, `tail` and `content` all held
  that hash. A larger file got only its 64 KiB `head` and `tail` in the hash
  phase. The content phase ran after the update phase. It read a file for
  `content` only when its size, `head` and `tail` matched another record's, from
  this scan or an earlier one. `content` was the whole file below 50 MiB, and
  gigabyte-spaced 1 MiB samples at or above. It never read a file gone or
  changed since its record was written. `report` and `trees` left out any record
  without a `content` hash. The `content` column is part of the version 1
  schema. Superseded by https://git.eeqj.de/sneak/sfdupes/issues/132
  (2026-09-22, branch `next`, https://git.eeqj.de/sneak/sfdupes/issues/61)
 - The dead `files.dat` references were removed from `Makefile`, `.gitignore` and
  `.dockerignore` (2026-09-21, branch `next`,
  https://git.eeqj.de/sneak/sfdupes/issues/22)
 - The lint-image pin comments and `FROM` form in `Dockerfile` and
  `Dockerfile.lint` were fixed. Both pins became the policy
  `# image:vX.Y.Z, YYYY-MM-DD` comment over a bare `FROM image@sha256:...`,
  without the false `(Debian-based)` note or the tag. Since
  https://git.eeqj.de/sneak/sfdupes/issues/95 the `Dockerfile`'s `lint` phase
  holds the only `golangci-lint` pin, in that form. `Dockerfile.lint` is gone,
  and so is `script/verify-lint-image-pin`, which compared the two pins
  (2026-08-10, branch `next`, https://git.eeqj.de/sneak/sfdupes/issues/25)
 - All linting ran in Docker, via `Dockerfile.lint` and `script/lint`. Per the
  owner ruling the linter is never installed on a host, and
  `golangci-lint config verify` runs before `golangci-lint run`.
  `script/bootstrap` stopped installing or pinning the linter, and
  `script/verify-linter-pin` was retired. Since
  https://git.eeqj.de/sneak/sfdupes/issues/95 both commands run in the
  `Dockerfile`'s `lint` phase. `script/lint` builds that phase alone, and the
  build stage depends on it through `COPY --from=lint /src/go.sum /dev/null`.
  `Dockerfile.lint` and `script/verify-lint-image-pin` are gone. Nothing inside
  an image build may run `docker`, so the phase calls `golangci-lint` directly
  (2026-08-10, branch `next`, https://git.eeqj.de/sneak/sfdupes/issues/46)
 - The Docker build stage's prerequisites were installed by running
  `script/bootstrap` instead of `apk add --no-cache make` inline.
  `script/verify-linter-pin` failed the build unless the linter copied from the
  lint stage was the version that `script/bootstrap` pinned. Builds then took up
  to 5m14s from an empty cache, mostly in a `chown -R` of the module cache,
  filed as https://git.eeqj.de/sneak/sfdupes/issues/43. Since
  https://git.eeqj.de/sneak/sfdupes/issues/95 the build stage installs `git` and
  `make` with `apk add --no-cache` and only compiles. The `lint` and `test`
  phases are the gates (2026-08-09, branch `dockerfile-bootstrap`,
  https://git.eeqj.de/sneak/sfdupes/issues/42)
 - The Docker layer cache is defeated for the gate steps, so `script/cibuild` and
  `script/docker` cannot report a pass they did not earn. The `Dockerfile`
  copies the tree before its gates. On an unchanged tree Docker served them from
  cache, and the build exited 0 without running them. The fix was a
  `CHECK_EPOCH` build argument. Since
  https://git.eeqj.de/sneak/sfdupes/issues/95 every `docker build` in `script/`
  passes a new `CACHEBUST` value instead. Every stage of the `Dockerfile`
  declares it before every step that checks or compiles the code. Run as root,
  the tests fail `TestScanHardlinkRunFailsTogether`, because root reads through
  the `chmod(0)` the test relies on. So the `test` phase runs them as `nobody`
  (2026-08-09, branch `cibuild-cache-bust`,
  https://git.eeqj.de/sneak/sfdupes/issues/32)
 - `script/bootstrap` checked the installed `golangci-lint` version instead of
  only its presence. The version lived only in `GOLANGCI_LINT_VERSION`, with the
  `go install` module reference derived from it. Any installed version that was
  not the pin was reinstalled, whether:
    - older;
    - newer;
    - absent;
    - unparseable.
    `go install` writes into `GOBIN`, or `GOPATH/bin`, while `make lint` ran the
    first `golangci-lint` on `PATH`. So bootstrap re-read the effective version
    after installing. On a mismatch it printed both paths and both versions and
    exited non-zero. It did not reorder `PATH` or delete anyone's binary. The
    `--version` call kept its stderr and was bounded by `timeout(1)` where that
    exists. `git`, `make` and `go` kept presence-only checks. The version check
    was verified by bootstrapping this host from v2.10.1 to v2.12.2, and again
    to a no-op. Stub runs of the script under `dash` covered:
    - a thirteen-input version-parse matrix;
    - a shadowed install, which must exit non-zero;
    - an install destination not on `PATH`;
    - `GOBIN` set;
    - a wedged binary, which must hit the timeout.
    `make check` and `make lint` were clean at v2.12.2, so v2.10.1 had not been
    hiding findings on `main`. Superseded by
    https://git.eeqj.de/sneak/sfdupes/issues/46, since the linter is no longer
    installed on a host (2026-08-09, branch `bootstrap-version-check`,
    https://git.eeqj.de/sneak/sfdupes/issues/24)
 - The hash worker pool unwinds on the error path. The pool is an owned,
  context-aware `hashPool`. Every blocking send in the feeder and the workers
  selects on `ctx.Done()`, and `jobs` is closed on every path out. `hashPhase`
  defers `pool.stop()`, which cancels and then drains `results` until the last
  goroutine has exited. Draining is what frees a worker parked on a send. `ctx`
  is passed from `cmd.Context()` as the first parameter, through:
    - `runScan`;
    - `syncScan`;
    - both worker pools;
    - the whole database layer.
    The walk pool gets the same treatment, plus a `ctx.Err()` guard after the
    walk. A cancelled walk yields a partial size census, and every file that it
    never reached looks vanished to the update phase. That phase's own `BeginTx`
    also fails on the cancelled context before deleting anything. The guard is
    still the barrier once an interrupted scan may commit what it has. Tests
    drive `run(scan)` against a database whose insert trigger aborts. They
    assert that the scan fails instead of hanging, and that the goroutine count
    returns to its pre-scan baseline. Other tests cancel a scan part-way through
    the walk, deterministically, by counting the scan's own checks of
    `ctx.Done()`. They assert that it stops at the guard with every record
    intact. It then holds a partial size census and a still-populated record
    index. Direct tests cover the remaining cancellation branches of both pools.
    They test:
    - `sendEvent`;
    - the walk workers;
    - `dispatchDirs`;
    - `feedHashJobs`;
    - `hashWorker`;
    - `hashPhase`.
    (2026-08-09, branch `hash-pool-cleanup`,
    https://git.eeqj.de/sneak/sfdupes/issues/6)
 - The database is closed on every fatal exit path. `fatalf` and its `os.Exit(1)`
  are gone. So the deferred `db.Close()` runs when a subcommand fails, and with
  it the SQLite WAL checkpoint. These return errors instead:
    - `runScan`;
    - `runReport`;
    - `runTrees`;
    - `loadRecords`;
    - `resolveRoots`.
    The single exit point is `run` in `internal/sfdupes/cli.go`. It maps a
    `fatalError`, anything a subcommand returned, to exit 1, and cobra's own
    argument and flag errors to exit 2. So a runtime failure is never reported
    as a usage error, nor printed with the usage text.
    `internal/sfdupes/cli_test.go` drives the CLI in-process and asserts the
    exit codes from README "Error handling" and the stdout/stderr split. It also
    checks that a fatal error after the database is open leaves no `-wal` or
    `-shm` file behind, for `scan`, `report` or `trees` (2026-08-09, branch
    `db-close-on-fatal`, https://git.eeqj.de/sneak/sfdupes/issues/4)
 - `golangci-lint` was updated to v2.12.2 with the canonical config, merged as
  `38a01bd`. The pinned linter in the `Dockerfile` lint stage and
  `script/bootstrap` went from v2.12.1 to v2.12.2, and `.golangci.yml` was
  replaced with the canonical file. Four thresholds now live under
  `linters.settings`, as the v2 schema requires, so they are applied:
    - `lll`;
    - `funlen`;
    - `cyclop`;
    - `dupl`.
    No new lint findings surfaced (2026-08-09, branch `golangci-v2.12.2`,
    https://git.eeqj.de/sneak/sfdupes/issues/3)
 - `Makefile` targets were converted to scripts-to-rule-them-all `script/`
  entrypoints, like the other managed repos. All 12 entrypoints exist:
    - `bootstrap`, `setup` and `projectname`;
    - `test`, `lint`, `fmt`, `fmt-check` and `check`;
    - `docker`, `cibuild`, `precommit` and `install-precommit`.
    Every `Makefile` target does nothing but call its script (2026-07-26, commit
    `3abeacf`, https://git.eeqj.de/sneak/sfdupes/issues/1)
 - The binary is the default `make` target. Plain `make` builds `sfdupes`, where
  it used to run `check` plus `build`. `make build` remains as an alias
  (2026-07-24, branch `make-default-target`)
 - The phases became scan-wide, with concurrent operands and batched updates. All
  operands seed the shared walk pool, and every pass runs once over the whole
  scan. So the totals and ETAs cover the whole scan. The per-operand walk, hash
  and update cycles and their stderr announcements are gone. The update pass
  writes in batches, each in its own transaction. The filesystem is
  authoritative and the database follows it, so one scan's changes need not land
  all at once (2026-07-24, branch `scan-wide-phases`)
 - The stat pass was split back out of the walk. Phases are strictly sequential
  again, per operand, with parallelism only inside each phase:
    - walk;
    - stat;
    - hash;
    - update.
    The walk enumerates paths with per-directory workers, and the stat pass
    lstats them with per-file workers. That restores the exact total and ETA of
    the stat bar (2026-07-24, branch `parallel-phases`)
 - Each operand is announced on stderr before its passes. With per-operand walk,
  hash and update cycles, a multi-operand run such as `scan /srv/*` showed pass
  totals that looked like the whole run's (2026-07-24, branch
  `scan-operand-progress`)
 - The walk became parallel. The walk pass was a single goroutine and took hours
  at about 20 million files on a busy pool. One ZFS server took 4 hours for 22
  million files. It is now a walk by a pool of per-directory workers that
  records size and mtime as it goes. That folds away the separate stat pass and
  halves the metadata reads. Each `PATH` operand commits in its own transaction,
  so an interrupted scan keeps completed operands (2026-07-24, branch
  `parallel-walk`)
 - `scan` gained a persistent database. It maintains an SQLite database that
  survives between runs, with the absolute path as each record's key. The driver
  is `modernc.org/sqlite`, pure Go, so cgo stays disabled. A rescan hashes only
  new or changed files, by mtime and size. It deletes the records of files
  vanished from under the scanned operands and leaves records outside them
  untouched. So `scan` can run daily from `cron`. `report` and `trees` read the
  database, with no positional arguments, instead of a scan stream. The database
  is at `/var/lib/sfdupes/db.sqlite`, and `SFDUPES_DATABASE` overrides that. WAL
  journaling plus a single-transaction update keep a report run during a scan
  safe (2026-07-24, branch `persistent-database`)
 - The `origin` remote, `git@git.eeqj.de:sneak/sfdupes.git`, was added. `v0.0.1`
  was tagged, and `main` and the tags were pushed (2026-07-23)
 - The `scan` command line was reworked. Required `PATH...` operands, parsed by
  cobra, replace the `/srv` `-root` default. The new `-x`, `--one-file-system`
  flag follows the GNU convention and stops at filesystem boundaries, which the
  walk crosses by default (2026-07-23, branch `scan-required-paths`)
 - The repo was brought into compliance with `REPO_POLICIES.md` (the version of
  2026-07-06), the existing repo checklist and the Go styleguide. The audit of
  2026-07-22 found these gaps, and the branch closed them:
    - `.gitignore`, with the standard patterns for secrets and for OS, editor
      and Go files. The compiled `sfdupes` binary and `files.dat` had been
      sitting untracked in the tree;
    - `.editorconfig`;
    - `LICENSE` and the README License section. MIT was assumed from house
      convention, for the owner to confirm;
    - `REPO_POLICIES.md` in the repo root;
    - the canonical `.golangci.yml`, with its 150 findings fixed, so that
      `make lint` is clean;
    - the `Makefile` targets the policy requires:
        - `test` and `lint`;
        - `fmt` and `fmt-check`;
        - `docker` and `hooks`.
        `check` depended on `build`, which wrote the binary. `make check` must
        not modify files, so `check` no longer depends on `build`;
    - a test suite, which the policy required with a 30-second timeout and the
      conditional `-v` rerun. At 64% coverage, it covers:
        - parsing and grouping;
        - digests and suppression;
        - hashing and the scan pipeline;
    - a multistage `Dockerfile` and `.dockerignore`. The `Dockerfile` had:
        - hash-pinned images;
        - a lint stage that failed fast;
        - a build stage that ran `make check`;
    - `.gitea/workflows/check.yml`, running `docker build .` on push with the
      checkout action pinned by commit SHA;
    - the README sections the policy requires. The first is a Description whose
      first line names the project, its purpose and category, its license and
      its author. Then come Getting Started and Rationale, and at the end TODO,
      License and Author;
    - the stale README non-goal "no git repository setup and no CI" removed;
    - the pre-commit hook, installed with `make hooks` once that target existed.
    The code was already `gofmt`-clean, so no standalone formatting commit was
    needed (2026-07-23, branch `repo-policy-compliance`)
 - `git init` was run, with a README-only first commit. The code baseline was
  committed on `main` (2026-07-22)
 - The `scan`, `report` and `trees` subcommands were implemented (pre-git
  history)
 # Future Steps
 - Possible later features, out of scope per README, are a byte-for-byte check of
@@ -5,10 +5,8 @@
 // KiB, and of the content. The content hash covers the whole file under
 // 100 MiB, and 1 MiB at each gigabyte at 100 MiB or more, so a large
 // file is never read in full. scan maintains a persistent SQLite
-// database of file signatures that the other subcommands read. The
+// database of file signatures (SFDUPES_DATABASE, default
-// database is SFDUPES_DATABASE, or by default /var/lib/sfdupes/db.sqlite
+// /var/lib/sfdupes/db.sqlite) that the other subcommands read.
 // for root and sfdupes/db.sqlite in the XDG state directory for any
 // other user.
 //
 // Usage:
 //
@@ -3,7 +3,7 @@ module sneak.berlin/go/sfdupes
 go 1.25.7
 require (
-	github.com/adrg/xdg v0.5.3
+	github.com/rivo/uniseg v0.4.7
 	github.com/schollz/progressbar/v3 v3.19.1
 	github.com/spf13/cobra v1.10.2
 	golang.org/x/sys v0.46.0
@@ -19,7 +19,6 @@ require (
 	github.com/mitchellh/colorstring v0.0.0-20190213212951-d06e56a500db // indirect
 	github.com/ncruces/go-strftime v1.0.0 // indirect
 	github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec // indirect
 	github.com/rivo/uniseg v0.4.7 // indirect
 	github.com/spf13/pflag v1.0.9 // indirect
 	modernc.org/libc v1.74.1 // indirect
 	modernc.org/mathutil v1.7.1 // indirect
@@ -1,5 +1,3 @@
 github.com/adrg/xdg v0.5.3 h1:xRnxJXne7+oWDatRhR1JLnvuccuIeCoBu2rtuLqQB78=
 github.com/adrg/xdg v0.5.3/go.mod h1:nlTsY+NNiCBGCK2tpm09vRqfVzrc2fLmXGpBLF0zlTQ=
 github.com/chengxilo/virtualterm v1.0.4 h1:Z6IpERbRVlfB8WkOmtbHiDbBANU7cimRIof7mk9/PwM=
 github.com/chengxilo/virtualterm v1.0.4/go.mod h1:DyxxBZz/x1iqJjFxTFcr6/x+jSpqN0iwWCOK1q10rlY=
 github.com/cpuguy83/go-md2man/v2 v2.0.6/go.mod h1:oOW0eioCTA6cOiMLiUPZOpcVxMig6NIQQ7OS05n1F4g=
@@ -358,8 +358,9 @@ func TestRunScanInterrupted(t *testing.T) {
 	stderr := captureStderr(t)
 	dir := buildSmokeTree(t)
-	err := runScan(t.Context(), []string{dir}, walkCancelWorkers, false,
+	opts := scanOptions{workers: walkCancelWorkers}
-		false, nil)
+
 	err := runScan(t.Context(), []string{dir}, opts)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -382,8 +383,7 @@ func TestRunScanInterrupted(t *testing.T) {
 	go func() {
 		defer close(done)
-		err = runScan(cancelledContext(t), []string{dir}, walkCancelWorkers,
+		err = runScan(cancelledContext(t), []string{dir}, opts)
 			false, false, nil)
 	}()
 	awaitReturn(t, done, "runScan")
@@ -410,8 +410,7 @@ func TestRunScanInterrupted(t *testing.T) {
 			got, before)
 	}
-	err = runScan(t.Context(), []string{dir}, walkCancelWorkers, false,
+	err = runScan(t.Context(), []string{dir}, opts)
 		false, nil)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -437,7 +436,7 @@ func TestRunScanInterruptedMidHash(t *testing.T) {
 	dir := buildWalkCancelTree(t)
 	err := runScan(newWalkClock(hashCancelAtDone), []string{dir},
-		walkCancelWorkers, false, false, nil)
+		scanOptions{workers: walkCancelWorkers})
 	if !errors.Is(err, errInterrupted) {
 		t.Fatalf("runScan interrupted mid-hash = %v, want %v",
 			err, errInterrupted)
@@ -32,17 +32,79 @@ const (
 	cmdDwim   = "dwim"
 )
 // databaseHelp is the paragraph of the root and scan help that names
 // the database (README "Location").
 const databaseHelp = "scan and dwim store what they find in a database " +
 	"file. report, trees\nand info read it. The file is $" + databaseEnv +
 	" when that is set and\nnot empty, and otherwise " +
 	defaultDatabasePath + ", where creating it\nneeds root.\n"
 // escapesHelp is the paragraph of the report and trees help on how
 // paths are escaped (README "Report output format").
 const escapesHelp = `Four characters in a path are escaped, so each row stays one line:
  \\  a backslash
  \t  a tab
  \n  a newline
  \r  a carriage return
 `
 // reportHelp, treesHelp, infoHelp and dwimHelp follow the one-line
 // summary in the help of their subcommands.
 const (
 	reportHelp = `The report is tab-separated text on stdout: a header line, then one
 row per duplicate file. The columns are:
  first   the path that sorts first, byte by byte, in its group of copies
  dupe    another copy of that file
  size    the file's size in bytes
 Rows are ordered by size, largest first, then by path.
 ` + escapesHelp
 	treesHelp = `The report is tab-separated text on stdout: a header line, then one
 row per duplicate directory tree. The columns are:
  first      the path that sorts first, byte by byte, in its group of copies
  dupe       another copy of that tree
  files      the number of regular files in one copy
  size       their total size in bytes
  disk_size  the bytes the dupe copy takes on disk
 Rows are ordered by size, largest first, then by path.
 ` + escapesHelp
 	infoHelp = `The details go to stdout, one per line. Each line holds a name and its
 value, separated by a tab:
  database                the path, and where it came from
  database file size      in bytes, then rounded, as 2147483648 (2.0 GiB)
  -wal file size          in bytes, then rounded; only if a -wal file exists
  modified                when the database file last changed, in UTC
  schema version          the version of the database's layout
  records                 the number of records
  size of recorded files  their total size, in bytes, then rounded
 `
 	dwimHelp = `dwim runs what "sfdupes scan /" runs with the same flags, then what
 "sfdupes trees" runs. Run it as root, so that the scan can read every
 file. The scan is stored in the database, as scan stores it, so
 "sfdupes trees" prints the report again later.
 `
 )
 // errNoSubcommand is returned by the root command when it is invoked
 // without a subcommand. That is a usage error, and the usage text
 // cobra prints for it is the whole message.
 var errNoSubcommand = errors.New("no subcommand")
-// errWorkersBelowOne is the usage error for a scan --workers value
+// errWorkersBelowOne is the usage error for a --workers value below 1.
 // below 1.
 var errWorkersBelowOne = errors.New("--workers must be at least 1")
-// errEmptyExcludeValue is the usage error for an empty scan --exclude
+// errEmptyExcludeValue is the usage error for an empty --exclude value,
-// value, as from --exclude "$DIR" with DIR unset. Taken as a path, it
+// as from --exclude "$DIR" with DIR unset. Taken as a path, it
 // would name the working directory.
 var errEmptyExcludeValue = errors.New("--exclude must not be empty")
@@ -122,14 +184,6 @@ func run(args []string, stdout, stderr io.Writer) int {
 	}
 }
 // databaseHelp says in sfdupes --help where the database is.
 const databaseHelp = `The database is the file SFDUPES_DATABASE names.
 When that is unset or empty, root uses /var/lib/sfdupes/db.sqlite. Any
 other user uses sfdupes/db.sqlite in the XDG state directory:
 $XDG_STATE_HOME, or ~/.local/state when that is unset or empty
 (~/Library/Application Support on macOS). An XDG_STATE_HOME that is
 not an absolute path is an error.`
 // newRootCommand builds the command tree. Everything on stdout is
 // machine-readable data, the version line included; all human-facing
 // output (help, usage, errors) goes to stderr.
@@ -148,12 +202,9 @@ func newRootCommand(stdout, stderr io.Writer) *cobra.Command {
 		return nil
 	})
 	short := "Find candidate duplicate files by size and head/tail/content SHA-256"
 	root := &cobra.Command{
 		Use:   "sfdupes",
-		Short: short,
+		Short: "Find candidate duplicate files by size and head/tail/content SHA-256",
 		Long:  short + ".\n\n" + databaseHelp,
 		Args:  cobra.NoArgs,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			if showVersion {
@@ -204,76 +255,116 @@ func newRootCommand(stdout, stderr io.Writer) *cobra.Command {
 		}),
 	}
-	dwimCmd := &cobra.Command{
+	root.Long = root.Short + ".\n\n" + databaseHelp
-		Use:   cmdDwim,
+	reportCmd.Long = reportCmd.Short + ".\n\n" + reportHelp
-		Short: "Scan / with the default excludes, then print the duplicate-tree report",
+	treesCmd.Long = treesCmd.Short + ".\n\n" + treesHelp
-		Args:  cobra.NoArgs,
+	infoCmd.Long = infoCmd.Short + ".\n\n" + infoHelp
 		RunE: runE(func(ctx context.Context, _ []string) error {
 			return runDwim(ctx, "/", stdout)
 		}),
 	}
-	root.AddCommand(newScanCommand(), reportCmd, treesCmd, infoCmd, dwimCmd)
+	root.AddCommand(newScanCommand(), reportCmd, treesCmd, infoCmd,
 		newDwimCommand(stdout))
 	return root
 }
-// newScanCommand builds the scan subcommand, with its --workers, -x,
+// scanOptions holds the values of the flags that scan and dwim share:
-// --no-default-excludes and --exclude flags. Its help lists the default
+// --workers, -x, --no-default-excludes and --exclude.
-// excludes of the system it runs on, and the filesystem types it never
+type scanOptions struct {
-// records anything on.
+	workers           int
 	oneFS             bool
 	noDefaultExcludes bool
 	excludePaths      []string
 }
 // scanFlagsUsage names the flags that scan and dwim share, for their
 // usage lines.
 const scanFlagsUsage = "[--workers N] [-x] [--no-default-excludes] " +
 	"[--exclude PATH]..."
 // addScanFlags adds the flags that scan and dwim share to cmd, which
 // stores their values in opts.
 func addScanFlags(cmd *cobra.Command, opts *scanOptions) {
 	cmd.Flags().IntVar(&opts.workers, "workers", runtime.NumCPU(),
 		"concurrent workers for the walk and hash phases")
 	cmd.Flags().BoolVarP(&opts.oneFS, "one-file-system", "x", false,
 		"do not cross filesystem boundaries")
 	cmd.Flags().BoolVar(&opts.noDefaultExcludes, "no-default-excludes",
 		false, "enter the default excludes, the paths listed above")
 	// A string array, not a slice, so a comma in a path is not a
 	// separator.
 	cmd.Flags().StringArrayVar(&opts.excludePaths, "exclude", nil,
 		"never enter or record `PATH` or anything below it; repeatable")
 }
 // check rejects the flag values that are usage errors, before the
 // command runs. It is the PreRunE of scan and dwim.
 func (o *scanOptions) check(cmd *cobra.Command, _ []string) error {
 	err := checkScanWorkers(cmd, o.workers)
 	if err != nil {
 		return err
 	}
 	return rejectEmptyExcludeValue(cmd, o.excludePaths)
 }
 // newScanCommand builds the scan subcommand. Its help names the
 // database, and lists the default excludes of the system it runs on and
 // the filesystem types it never records anything on.
 func newScanCommand() *cobra.Command {
-	var (
+	var opts scanOptions
 		scanWorkers           int
 		scanOneFS             bool
 		scanNoDefaultExcludes bool
 		scanExclude           []string
 	)
 	short := "Walk trees and synchronize the scan database"
 	scanCmd := &cobra.Command{
-		Use: cmdScan + " [--workers N] [-x] [--no-default-excludes] " +
+		Use: cmdScan + " " + scanFlagsUsage + " PATH...",
 			"[--exclude PATH]... PATH...",
 		// The Use line already names every flag, so cobra must not
 		// append its generic "[flags]" to it.
 		DisableFlagsInUseLine: true,
 		Short:                 short,
-		Long:                  short + ".\n\n" + defaultExcludesHelp(runtime.GOOS),
+		Long: short + ".\n\n" + databaseHelp + "\n" +
-		Args:                  cobra.MinimumNArgs(1),
+			defaultExcludesHelp(runtime.GOOS),
-		PreRunE: func(cmd *cobra.Command, _ []string) error {
+		Args:    cobra.MinimumNArgs(1),
-			err := checkScanWorkers(cmd, scanWorkers)
+		PreRunE: opts.check,
 			if err != nil {
 				return err
 			}
 			return rejectEmptyExcludeValue(cmd, scanExclude)
 		},
 		RunE: runE(func(ctx context.Context, args []string) error {
 			ctx, stop := interruptContext(ctx)
 			defer stop()
-			return runScan(ctx, args, scanWorkers, scanOneFS,
+			return runScan(ctx, args, opts)
 				scanNoDefaultExcludes, scanExclude)
 		}),
 	}
-	scanCmd.Flags().IntVar(&scanWorkers, "workers", runtime.NumCPU(),
+	addScanFlags(scanCmd, &opts)
 		"concurrent workers for the walk and hash phases")
 	scanCmd.Flags().BoolVarP(&scanOneFS, "one-file-system", "x", false,
 		"do not cross filesystem boundaries")
 	scanCmd.Flags().BoolVar(&scanNoDefaultExcludes, "no-default-excludes",
 		false, "enter the default excludes, the paths listed above")
 	// A string array, not a slice, so a comma in a path is not a
 	// separator.
 	scanCmd.Flags().StringArrayVar(&scanExclude, "exclude", nil,
 		"never enter or record `PATH` or anything below it; repeatable")
 	return scanCmd
 }
-// checkScanWorkers rejects a scan --workers value below 1. That is a
+// newDwimCommand builds the dwim subcommand, which takes the scan flags
-// usage error reported in one line: cobra prints the returned message
+// with the meaning they have for scan. Its help says what dwim runs,
-// without the usage text, and run exits 2.
+// then lists the default excludes and the filesystem types the scan
 // never records anything on.
 func newDwimCommand(stdout io.Writer) *cobra.Command {
 	var opts scanOptions
 	short := "Scan /, then print the duplicate-tree report"
 	dwimCmd := &cobra.Command{
 		Use:                   cmdDwim + " " + scanFlagsUsage,
 		DisableFlagsInUseLine: true,
 		Short:                 short,
 		Long: short + ".\n\n" + dwimHelp + "\n" +
 			defaultExcludesHelp(runtime.GOOS),
 		Args:    cobra.NoArgs,
 		PreRunE: opts.check,
 		RunE: runE(func(ctx context.Context, _ []string) error {
 			return runDwim(ctx, "/", opts, stdout)
 		}),
 	}
 	addScanFlags(dwimCmd, &opts)
 	return dwimCmd
 }
 // checkScanWorkers rejects a --workers value below 1. That is a usage
 // error reported in one line: cobra prints the returned message without
 // the usage text, and run exits 2.
 func checkScanWorkers(cmd *cobra.Command, workers int) error {
 	if workers >= 1 {
 		return nil
@@ -284,7 +375,7 @@ func checkScanWorkers(cmd *cobra.Command, workers int) error {
 	return fmt.Errorf("%w, got %d", errWorkersBelowOne, workers)
 }
-// rejectEmptyExcludeValue rejects an empty scan --exclude value. That
+// rejectEmptyExcludeValue rejects an empty --exclude value. That
 // is a usage error reported in one line, as for --workers below 1.
 func rejectEmptyExcludeValue(cmd *cobra.Command, excludePaths []string) error {
 	if !slices.Contains(excludePaths, "") {
@@ -15,7 +15,6 @@ import (
 	"strings"
 	"testing"
 	"github.com/adrg/xdg"
 	"golang.org/x/sys/unix"
 )
@@ -23,6 +22,12 @@ import (
 // error prints and a runtime failure must not.
 const usageMarker = "Usage:"
 // helpFlag asks for the help text.
 const helpFlag = "--help"
 // workersFlag is the scan and dwim flag that sets the worker count.
 const workersFlag = "--workers"
 // TestMain stops the tests at once, saying why, when their temporary
 // directory is not on a persistent filesystem: scan records nothing
 // there (README "Rules for the walk"), so most scan tests would fail
@@ -554,17 +559,13 @@ func TestRunNamesDefaultDatabase(t *testing.T) {
 	// line.
 	t.Setenv(databaseEnv, "")
 	dbPath, err := defaultDatabasePath(os.Geteuid())
 	if err != nil {
 		t.Fatal(err)
 	}
 	// Whether scan calls the database new depends on that machine too.
-	scanWant := "scan: database " + dbPath + " (default)\n"
+	scanWant := "scan: database " + defaultDatabasePath + " (default)\n"
-	_, err = os.Stat(dbPath)
+	_, err := os.Stat(defaultDatabasePath)
 	if errors.Is(err, fs.ErrNotExist) {
-		scanWant = "scan: new database " + dbPath + " (default)\n"
+		scanWant = "scan: new database " + defaultDatabasePath +
 			" (default)\n"
 	}
 	missing := filepath.Join(t.TempDir(), "nope")
@@ -575,8 +576,8 @@ func TestRunNamesDefaultDatabase(t *testing.T) {
 	}{
 		cmdScan: {
 			run: func() error {
-				return runScan(t.Context(), []string{missing}, 1, false, false,
+				return runScan(t.Context(), []string{missing},
-					nil)
+					scanOptions{workers: 1})
 			},
 			want: scanWant,
 		},
@@ -584,21 +585,21 @@ func TestRunNamesDefaultDatabase(t *testing.T) {
 			run: func() error {
 				return runReport(cancelledContext(t), io.Discard)
 			},
-			want: "report: database " + dbPath + " (default)\n" +
+			want: "report: database " + defaultDatabasePath + " (default)\n" +
 				reportOpenLine + "\n" + reportOpenLine + "\n",
 		},
 		cmdTrees: {
 			run: func() error {
 				return runTrees(cancelledContext(t), io.Discard)
 			},
-			want: "trees: database " + dbPath + " (default)\n" +
+			want: "trees: database " + defaultDatabasePath + " (default)\n" +
 				treesOpenLine + "\n" + treesOpenLine + "\n",
 		},
 		cmdInfo: {
 			run: func() error {
 				return runInfo(cancelledContext(t), io.Discard)
 			},
-			want: "info: database " + dbPath + " (default)\n" +
+			want: "info: database " + defaultDatabasePath + " (default)\n" +
 				infoOpenLine + "\n" + infoOpenLine + "\n",
 		},
 	}
@@ -667,7 +668,7 @@ func TestRunScanRejectsWorkersBelowOne(t *testing.T) {
 			var stdout, stderr bytes.Buffer
-			args := []string{cmdScan, "--workers", workers, t.TempDir()}
+			args := []string{cmdScan, workersFlag, workers, t.TempDir()}
 			code := run(args, &stdout, &stderr)
 			if code != exitUsage {
@@ -698,7 +699,7 @@ func TestRunHelp(t *testing.T) {
 	// README §Settings: help goes to stderr, exits 0, and leaves stdout
 	// empty.
-	cases := [][]string{{"--help"}, {"-h"}, {cmdScan, "--help"}}
+	cases := [][]string{{helpFlag}, {"-h"}, {cmdScan, helpFlag}}
 	for _, args := range cases {
 		var stdout, stderr bytes.Buffer
@@ -717,22 +718,6 @@ func TestRunHelp(t *testing.T) {
 			t.Errorf("run(%v) stdout = %q, want nothing (data only)",
 				args, got)
 		}
 		if args[0] == cmdScan {
 			continue
 		}
 		// README §Location: sfdupes --help says where the database is,
 		// and that XDG_STATE_HOME must be an absolute path.
 		for _, want := range []string{
 			databaseEnv, rootDatabasePath, stateHomeEnv, "~/.local/state",
 			"not an absolute path is an error",
 		} {
 			if !strings.Contains(stderr.String(), want) {
 				t.Errorf("run(%v) stderr = %q, want it to name %q",
 					args, stderr.String(), want)
 			}
 		}
 	}
 	// The scan help lists --exclude with its argument.
@@ -775,6 +760,73 @@ func TestRunScanUsageLine(t *testing.T) {
 	}
 }
 func TestRunHelpDescribesDatabaseAndOutput(t *testing.T) {
 	t.Parallel()
 	// README §Settings: the help names the database, and says what
 	// report, trees, info and dwim print.
 	database := []string{
 		"scan and dwim store", databaseEnv, defaultDatabasePath, "needs root",
 	}
 	escapes := []string{`\\`, `\t`, `\n`, `\r`}
 	// The subcommand whose help is printed; none for the root.
 	cases := []struct {
 		subcommand []string
 		want       []string
 	}{
 		{nil, database},
 		{[]string{cmdScan}, database},
 		{
 			[]string{cmdReport},
 			append([]string{
 				"tab-separated", "\n  first ", "\n  dupe ", "\n  size ",
 				"largest first",
 			}, escapes...),
 		},
 		{
 			[]string{cmdTrees},
 			append([]string{
 				"tab-separated", "\n  first ", "\n  dupe ", "\n  files ",
 				"\n  size ", "\n  disk_size ", "largest first",
 			}, escapes...),
 		},
 		{
 			[]string{cmdInfo},
 			[]string{
 				"\n  database ", "\n  database file size ",
 				"\n  -wal file size ", "\n  modified ",
 				"\n  schema version ", "\n  records ",
 				"\n  size of recorded files ",
 			},
 		},
 		{
 			[]string{cmdDwim},
 			[]string{
 				"sfdupes scan /", "as root", "sfdupes trees", "database",
 			},
 		},
 	}
 	for _, tc := range cases {
 		var stdout, stderr bytes.Buffer
 		args := slices.Concat(tc.subcommand, []string{helpFlag})
 		code := run(args, &stdout, &stderr)
 		if code != exitOK {
 			t.Fatalf("run(%v) = %d, want %d", args, code, exitOK)
 		}
 		for _, want := range tc.want {
 			if !strings.Contains(stderr.String(), want) {
 				t.Errorf("run(%v) help lacks %q:\n%s",
 					args, want, stderr.String())
 			}
 		}
 	}
 }
 func TestRunVersion(t *testing.T) {
 	t.Parallel()
@@ -1557,75 +1609,6 @@ func TestRunDatabasePathUsedAsGiven(t *testing.T) {
 	})
 }
 func TestRunNonRootUsesStateDirectory(t *testing.T) {
 	// README §Location: without SFDUPES_DATABASE, a user other than
 	// root keeps the database in the XDG state directory. scan creates
 	// the missing directories with mode 0700, and report and trees read
 	// the same file.
 	if os.Geteuid() == 0 {
 		t.Skip("root uses " + rootDatabasePath)
 	}
 	t.Cleanup(xdg.Reload)
 	state := filepath.Join(t.TempDir(), "state")
 	t.Setenv(stateHomeEnv, state)
 	t.Setenv(databaseEnv, "")
 	xdg.Reload()
 	assertRunsUseDatabase(t, filepath.Join(state, "sfdupes"), "db.sqlite")
 	for _, dir := range []string{state, filepath.Join(state, "sfdupes")} {
 		fi, err := os.Stat(dir)
 		if err != nil {
 			t.Fatal(err)
 		}
 		if got := fi.Mode().Perm(); got != stateDirPerm {
 			t.Errorf("%s mode = %#o, want %#o", dir, got, stateDirPerm)
 		}
 	}
 }
 func TestRunRelativeStateHomeFails(t *testing.T) {
 	// README §Location: without SFDUPES_DATABASE, a user other than
 	// root whose XDG_STATE_HOME is not an absolute path gets an error
 	// naming it from every subcommand, which exits 1 before it does
 	// anything else.
 	if os.Geteuid() == 0 {
 		t.Skip("root does not use " + stateHomeEnv)
 	}
 	t.Setenv(stateHomeEnv, "relative/state")
 	t.Setenv(databaseEnv, "")
 	want := "sfdupes: " + stateHomeEnv +
 		" must be an absolute path, got \"relative/state\"\n"
 	// A scan that got past the check would stop at this missing
 	// operand, before it creates anything.
 	missing := filepath.Join(t.TempDir(), "missing")
 	for _, args := range [][]string{
 		{cmdScan, missing}, {cmdReport}, {cmdTrees}, {cmdInfo},
 	} {
 		var stdout, stderr bytes.Buffer
 		code := run(args, &stdout, &stderr)
 		if code != exitFatal || stderr.String() != want {
 			t.Errorf("run(%v) = %d with stderr %q, want %d and %q",
 				args, code, stderr.String(), exitFatal, want)
 		}
 	}
 	// dwim scans /, so runDwim gets the missing operand instead.
 	err := runDwim(t.Context(), missing, io.Discard)
 	if !errors.Is(err, errStateHomeNotAbsolute) {
 		t.Errorf("runDwim: error = %v, want %v", err,
 			errStateHomeNotAbsolute)
 	}
 }
 // holdScanLock takes the lock on the database at path, as a running
 // scan does, and holds it until the test ends. It fails the test when
 // the lock is already held.
@@ -15,40 +15,28 @@ import (
 	"strings"
 	"time"
 	"github.com/adrg/xdg"
 	"golang.org/x/sys/unix"
 	// The pure-Go SQLite driver, registered as "sqlite"; keeps cgo
 	// disabled.
 	_ "modernc.org/sqlite"
 )
-// rootDatabasePath is the database root uses when SFDUPES_DATABASE is
+// defaultDatabasePath is where the persistent scan database lives when
-// not set.
+// SFDUPES_DATABASE is not set.
-const rootDatabasePath = "/var/lib/sfdupes/db.sqlite"
+const defaultDatabasePath = "/var/lib/sfdupes/db.sqlite"
 // databaseEnv is the environment variable that overrides the database
 // path.
 const databaseEnv = "SFDUPES_DATABASE"
 // stateHomeEnv is the environment variable that names the XDG state
 // directory.
 const stateHomeEnv = "XDG_STATE_HOME"
 // schemaVersion is the database schema version this build reads and
 // writes, stored in PRAGMA user_version.
 const schemaVersion = 1
-// dbDirPerm is the mode for a directory scan creates for root's
+// dbDirPerm is the mode for a database parent directory created by
-// default database or for SFDUPES_DATABASE.
+// scan.
 const dbDirPerm = 0o755
 // stateDirPerm is the mode for a directory scan creates for the
 // database at a user's default path in the XDG state directory. It is
 // the mode the XDG Base Directory specification asks for, and it keeps
 // other users from reading the database, which lists every scanned
 // path.
 const stateDirPerm = 0o700
 // dbFilePerm is the mode for a database file created by scan, the mode
 // SQLite gives a database file it creates.
 const dbFilePerm = 0o644
@@ -156,48 +144,15 @@ var errScanRunning = errors.New("another scan is running")
 // 32 bytes of a SHA-256.
 var errHashSize = errors.New("hash is not 32 bytes")
 // errStateHomeNotAbsolute reports an XDG_STATE_HOME that is set to a
 // path that is not absolute.
 var errStateHomeNotAbsolute = errors.New(
 	stateHomeEnv + " must be an absolute path")
 // defaultDatabasePath is the database used when SFDUPES_DATABASE is not
 // set: rootDatabasePath for root (euid 0), and db.sqlite in the
 // directory sfdupes under the XDG state directory for any other user.
 // xdg reads XDG_STATE_HOME and HOME once, when the program starts. For
 // any other user, an XDG_STATE_HOME that is set and not an absolute
 // path is an error, where xdg would use its default instead. The path
 // is joined as text, not cleaned, for the reason absolutePath gives.
 func defaultDatabasePath(euid int) (string, error) {
 	if euid == 0 {
 		return rootDatabasePath, nil
 	}
 	stateHome := os.Getenv(stateHomeEnv)
 	if stateHome != "" && !filepath.IsAbs(stateHome) {
 		return "", fmt.Errorf("%w, got %q", errStateHomeNotAbsolute,
 			stateHome)
 	}
 	stateDir := strings.TrimSuffix(xdg.StateHome, "/")
 	return stateDir + "/sfdupes/db.sqlite", nil
 }
 // databasePath resolves the database location: SFDUPES_DATABASE when
-// set and non-empty, defaultDatabasePath otherwise. It returns the
+// set and non-empty, the compiled-in default otherwise. It returns the
 // path, made absolute by absolutePath, and where the path came from,
 // "default" or "from SFDUPES_DATABASE", for the line each subcommand
 // prints first on stderr.
 func databasePath() (string, string, error) {
-	path, source := os.Getenv(databaseEnv), "from "+databaseEnv
+	path, source := defaultDatabasePath, "default"
-	if path == "" {
+	if p := os.Getenv(databaseEnv); p != "" {
-		def, err := defaultDatabasePath(os.Geteuid())
+		path, source = p, "from "+databaseEnv
 		if err != nil {
 			return "", "", err
 		}
 		path, source = def, "default"
 	}
 	abs, err := absolutePath(path)
@@ -233,23 +188,15 @@ func absolutePath(path string) (string, error) {
 // createDatabaseDirectory creates the directory the database at path
 // goes in, and any directory above it, if missing. path is absolute, as
-// databasePath returns it. Each directory gets mode dbDirPerm, or
+// databasePath returns it. The directory is path with its last element
-// stateDirPerm when databasePath uses a user's default path in the XDG
+// cut off as text, by filepath.Split. filepath.Dir would clean it,
-// state directory: the user is not root and SFDUPES_DATABASE is unset
+// dropping each ".." together with the directory name before it; when
-// or empty. The directory is path with its last element cut off as
+// that name is a symlink, the cleaned path names another directory than
-// text, by filepath.Split. filepath.Dir would clean it, dropping each
+// the one the system reaches when it opens path.
 // ".." together with the directory name before it; when that name is a
 // symlink, the cleaned path names another directory than the one the
 // system reaches when it opens path.
 func createDatabaseDirectory(path string) error {
 	dir, _ := filepath.Split(path)
-	perm := os.FileMode(dbDirPerm)
+	err := os.MkdirAll(dir, dbDirPerm)
 	if os.Geteuid() != 0 && os.Getenv(databaseEnv) == "" {
 		perm = stateDirPerm
 	}
 	err := os.MkdirAll(dir, perm)
 	if err != nil {
 		return fmt.Errorf("create database directory: %w", err)
 	}
@@ -9,13 +9,10 @@ import (
 	"io/fs"
 	"os"
 	"path/filepath"
 	"runtime"
 	"slices"
 	"strings"
 	"testing"
 	"time"
 	"github.com/adrg/xdg"
 )
 // testDBPath returns a database path inside a fresh temp dir, with
@@ -59,16 +56,11 @@ func TestDatabasePath(t *testing.T) {
 	t.Chdir(dir)
 	defaultPath, err := defaultDatabasePath(os.Geteuid())
 	if err != nil {
 		t.Fatal(err)
 	}
 	fromEnv := "from " + databaseEnv
 	cases := []struct {
 		env, path, source string
 	}{
-		{"", defaultPath, "default"},
+		{"", defaultDatabasePath, "default"},
 		{"/custom/place.sqlite", "/custom/place.sqlite", fromEnv},
 		{"/custom/link/../place.sqlite", "/custom/link/../place.sqlite",
 			fromEnv},
@@ -97,48 +89,6 @@ func TestDatabasePath(t *testing.T) {
 	}
 }
 func TestDefaultDatabasePath(t *testing.T) {
 	// README §Location: root's database is /var/lib/sfdupes/db.sqlite.
 	// Any other user's is db.sqlite in sfdupes under XDG_STATE_HOME, or
 	// under ~/.local/state when XDG_STATE_HOME is unset or empty. For
 	// that user, an XDG_STATE_HOME that is not an absolute path is an
 	// error.
 	if runtime.GOOS != goosLinux {
 		t.Skip("macOS has another default state directory")
 	}
 	t.Cleanup(xdg.Reload)
 	t.Setenv("HOME", "/home/someone")
 	cases := []struct {
 		euid      int
 		stateHome string
 		want      string
 		wantErr   error
 	}{
 		{0, "", rootDatabasePath, nil},
 		{0, "/elsewhere/state", rootDatabasePath, nil},
 		{0, "relative/state", rootDatabasePath, nil},
 		{1000, "", "/home/someone/.local/state/sfdupes/db.sqlite", nil},
 		{1000, "relative/state", "", errStateHomeNotAbsolute},
 		{1000, "~/state", "", errStateHomeNotAbsolute},
 		{1000, "/elsewhere/state", "/elsewhere/state/sfdupes/db.sqlite", nil},
 		{1000, "/elsewhere/state/", "/elsewhere/state/sfdupes/db.sqlite", nil},
 	}
 	for _, tc := range cases {
 		t.Setenv(stateHomeEnv, tc.stateHome)
 		xdg.Reload()
 		got, err := defaultDatabasePath(tc.euid)
 		if got != tc.want || !errors.Is(err, tc.wantErr) {
 			t.Errorf("defaultDatabasePath(%d) with %s=%q = %q, %v; want %q, %v",
 				tc.euid, stateHomeEnv, tc.stateHome, got, err, tc.want,
 				tc.wantErr)
 		}
 	}
 }
 func TestOpenScanDatabaseCreates(t *testing.T) {
 	t.Parallel()
@@ -5,20 +5,20 @@ import (
 	"fmt"
 	"io"
 	"os"
 	"runtime"
 )
 // runDwim implements the dwim subcommand: it runs what "sfdupes scan
-// root" runs with no flags, then what "sfdupes trees" runs, and ends
+// root" runs with the scan flags in opts, then what "sfdupes trees"
-// with a line on stderr saying how to print the report again. The dwim
+// runs, and ends with a line on stderr saying how to print the report
-// command passes "/" as root. It catches SIGINT and SIGTERM as scan
+// again. The dwim command passes "/" as root. It catches SIGINT and
-// does, but only during the scan. An error from the scan, an interrupt
+// SIGTERM as scan does, but only during the scan. An error from the
-// included, ends it before the report. During the report, a signal
+// scan, an interrupt included, ends it before the report. During the
-// ends it at once, as it ends trees.
+// report, a signal ends it at once, as it ends trees.
-func runDwim(ctx context.Context, root string, stdout io.Writer) error {
+func runDwim(
 	ctx context.Context, root string, opts scanOptions, stdout io.Writer,
 ) error {
 	scanCtx, stop := interruptContext(ctx)
-	err := runScan(scanCtx, []string{root}, runtime.NumCPU(), false, false,
+	err := runScan(scanCtx, []string{root}, opts)
 		nil)
 	stop()
@@ -2,7 +2,10 @@ package sfdupes //nolint:testpackage // calls the unexported runDwim
 import (
 	"bytes"
 	"errors"
 	"os"
 	"path/filepath"
 	"runtime"
 	"strings"
 	"testing"
 )
@@ -28,7 +31,7 @@ func TestRunDwimPrintsLargestTreesFirst(t *testing.T) {
 	stderr := captureStderr(t)
-	err := runDwim(t.Context(), root, &stdout)
+	err := runDwim(t.Context(), root, scanOptions{workers: 1}, &stdout)
 	if err != nil {
 		t.Fatalf("runDwim: %v; stderr: %s", err, stderr())
 	}
@@ -67,7 +70,7 @@ func TestRunDwimScanErrorPrintsNoReport(t *testing.T) {
 	stderr := captureStderr(t)
-	err := runDwim(t.Context(), missing, &stdout)
+	err := runDwim(t.Context(), missing, scanOptions{workers: 1}, &stdout)
 	if err == nil {
 		t.Fatal("runDwim on a missing root: error = nil, want it fatal")
 	}
@@ -81,3 +84,127 @@ func TestRunDwimScanErrorPrintsNoReport(t *testing.T) {
 		t.Errorf("stderr = %q, want nothing from trees or dwim", got)
 	}
 }
 func TestRunDwimExcludeLeavesTreeOut(t *testing.T) {
 	// dwim passes its --exclude paths to the scan: an excluded copy is
 	// not recorded, so its pair is not reported.
 	t.Setenv(databaseEnv, testDBPath(t))
 	root := realTempDir(t)
 	kept := []string{
 		filepath.Dir(writeFile(t, root, "a1/f.bin", pattern(1, 300))),
 		filepath.Dir(writeFile(t, root, "a2/f.bin", pattern(1, 300))),
 	}
 	writeFile(t, root, "b1/f.bin", pattern(2, 5000))
 	excluded := filepath.Dir(writeFile(t, root, "b2/f.bin", pattern(2, 5000)))
 	var stdout bytes.Buffer
 	stderr := captureStderr(t)
 	opts := scanOptions{workers: 1, excludePaths: []string{excluded}}
 	err := runDwim(t.Context(), root, opts, &stdout)
 	if err != nil {
 		t.Fatalf("runDwim: %v; stderr: %s", err, stderr())
 	}
 	lines := strings.Split(strings.TrimSuffix(stdout.String(), "\n"), "\n")
 	if len(lines) != 2 {
 		t.Fatalf("stdout = %q, want a header and one group",
 			stdout.String())
 	}
 	want := kept[0] + "\t" + kept[1] + "\t1\t300\t"
 	if !strings.HasPrefix(lines[1], want) {
 		t.Errorf("group = %q, want it to start %q", lines[1], want)
 	}
 	skipped := "scan: skipped " + excluded + " (--exclude)\n"
 	if got := stderr(); !strings.Contains(got, skipped) {
 		t.Errorf("stderr = %q, want it to contain %q", got, skipped)
 	}
 }
 func TestRunDwimTakesScanFlags(t *testing.T) {
 	// The dwim command parses and checks the scan flags as scan does.
 	// Each case stops before the walk of / begins, and before the
 	// database is created. "dwim --exclude /" excludes its own operand.
 	cases := map[string]struct {
 		args []string
 		code int
 		want string
 	}{
 		"--exclude /": {
 			[]string{cmdDwim, excludeFlag, "/"},
 			exitFatal,
 			"sfdupes: scan /: operand excluded by --exclude /\n",
 		},
 		"--exclude empty": {
 			[]string{cmdDwim, excludeFlag, ""},
 			exitUsage,
 			"Error: --exclude must not be empty\n",
 		},
 		"--workers 0": {
 			[]string{cmdDwim, workersFlag, "0", "-x", "--no-default-excludes"},
 			exitUsage,
 			"Error: --workers must be at least 1, got 0\n",
 		},
 	}
 	for name, tc := range cases {
 		t.Run(name, func(t *testing.T) {
 			path := testDBPath(t)
 			t.Setenv(databaseEnv, path)
 			stdout := captureStdout(t)
 			stderr := captureStderr(t)
 			code := run(tc.args, os.Stdout, os.Stderr)
 			if code != tc.code {
 				t.Errorf("run(%q) = %d, want %d", tc.args, code, tc.code)
 			}
 			if !strings.HasSuffix(stderr(), tc.want) || stdout() != "" {
 				t.Errorf("stdout, stderr = %q, %q, want \"\" and stderr "+
 					"ending %q", stdout(), stderr(), tc.want)
 			}
 			_, err := os.Lstat(path)
 			if !errors.Is(err, os.ErrNotExist) {
 				t.Errorf("lstat %s: %v, want no database", path, err)
 			}
 		})
 	}
 }
 func TestRunDwimHelpListsScanFlags(t *testing.T) {
 	t.Parallel()
 	// README "Subcommands" shows this usage line for dwim.
 	const want = "\n  sfdupes dwim [--workers N] [-x] [--no-default-excludes] " +
 		"[--exclude PATH]...\n"
 	var stdout, stderr bytes.Buffer
 	run([]string{cmdDwim, "-h"}, &stdout, &stderr)
 	if !strings.Contains(stderr.String(), want) {
 		t.Errorf("dwim -h stderr = %q, want the usage line %q",
 			stderr.String(), want)
 	}
 	if !strings.Contains(stderr.String(), excludeFlag+" PATH") {
 		t.Errorf("dwim -h stderr = %q, want %s PATH", stderr.String(),
 			excludeFlag)
 	}
 	// README "Settings": the help lists the default excludes and the
 	// filesystem types the walk never records anything on.
 	help := strings.TrimSpace(defaultExcludesHelp(runtime.GOOS))
 	if !strings.Contains(stderr.String(), help) {
 		t.Errorf("dwim -h stderr = %q, want it to hold %q", stderr.String(),
 			help)
 	}
 }
@@ -254,7 +254,7 @@ func readMountInfo(mountinfo io.Reader) (map[uint64]string, error) {
 	return devices, lines.Err()
 }
-// defaultExcludesHelp describes, for the scan command's help, the
+// defaultExcludesHelp describes, for the scan and dwim help, the
 // default excludes of the system goos names and, where the scan lists
 // the mounted filesystems, the types it never records anything on.
 func defaultExcludesHelp(goos string) string {
@@ -9,8 +9,10 @@ import (
 	"strings"
 	"sync"
 	"time"
 	"unicode"
 	"unicode/utf8"
 	"github.com/rivo/uniseg"
 	"github.com/schollz/progressbar/v3"
 	"golang.org/x/term"
 )
@@ -116,7 +118,8 @@ type drawnCount struct {
 // terminal's width. A phase with an exact total ends the line with its
 // percent and bar, at the terminal's right edge, when the terminal has
 // room for them. It is drawn again every redrawInterval, so its elapsed
-// time keeps moving while the phase waits for its next item. When
+// time keeps moving while the phase waits for its next item. Each draw
 // of the walk shows the path it reached last on the line below. When
 // stderr is not a TTY it emits no ANSI redraws: it prints line as the
 // phase starts, every plainInterval while it runs, and as it ends.
 //
@@ -141,6 +144,7 @@ type progress struct {
 	estimate   bool
 	waitingFor string
 	stalledOn  string
 	path       string // the path the walk reached last; "" for none
 	count      int64
 	start      time.Time // when the phase started, for the elapsed time
 	rateStart  time.Time // when the count started, for the time remaining
@@ -239,6 +243,82 @@ func (p *progress) draw() {
 	// less the terminal's last column, which spinnerMargin keeps clear. A
 	// bar's cells take one column each but more than one byte.
 	p.widest = max(p.widest, utf8.RuneCountInString(text)+spinnerMargin-1)
 	if p.path != "" {
 		// The library draws the path on the line below and returns to
 		// the phase's line. The path is escaped as warnings are, and its
 		// other control characters are written out, so that the terminal
 		// shows them instead of acting on them. It stays clear of the
 		// last column, so that no terminal wraps it.
 		shown := escapeControlChars(escapePath(p.path))
 		_ = p.bar.AddDetail(cutToColumns(shown, width-1))
 	}
 }
 // escapeControlChars returns s with each control character written as
 // \x and its code in two hex digits, as \x1b for the escape character.
 // The control characters are U+0000 to U+001F, U+007F and U+0080 to
 // U+009F, as unicode.IsControl reports them. A byte from 0x80 to 0x9F
 // that is not part of a valid UTF-8 character is written the same way,
 // as \x9b, since a terminal not in UTF-8 mode acts on it. Every other
 // byte is kept as it is.
 func escapeControlChars(s string) string {
 	var b strings.Builder
 	for rest := s; rest != ""; {
 		char, size := utf8.DecodeRuneInString(rest)
 		if char == utf8.RuneError && size == 1 {
 			// Not part of a valid UTF-8 character. A terminal not in
 			// UTF-8 mode reads the byte as the character with its code,
 			// so that 0x9b is a control character there and 0xe9 is not.
 			char = rune(rest[0])
 		}
 		if unicode.IsControl(char) {
 			fmt.Fprintf(&b, `\x%02x`, char)
 		} else {
 			b.WriteString(rest[:size])
 		}
 		rest = rest[size:]
 	}
 	return b.String()
 }
 // cutToColumns returns s cut to at most columns terminal columns, at a
 // character boundary. A wide character, as in Chinese, takes two
 // columns.
 func cutToColumns(s string, columns int) string {
 	used, end, state := 0, 0, -1
 	for rest := s; rest != ""; {
 		char, next, width, nextState := uniseg.FirstGraphemeClusterInString(
 			rest, state)
 		if used+width > columns {
 			break
 		}
 		used += width
 		end += len(char)
 		rest, state = next, nextState
 	}
 	return s[:end]
 }
 // clear erases the display from the terminal: its line, and the path on
 // the line below when one is shown. p.mu must be held.
 func (p *progress) clear() {
 	if p.bar == nil {
 		return
 	}
 	if p.path != "" {
 		_ = p.bar.AddDetail("")
 	}
 	_ = p.bar.Clear()
 }
 // newBar has the library make what draw draws: its spinner, followed by
@@ -263,6 +343,8 @@ func (p *progress) newBar(width int) {
 		// The text carries the elapsed time and the time remaining.
 		progressbar.OptionSetElapsedTime(false),
 		progressbar.OptionSetPredictTime(false),
 		// The line below the phase's line, for the walk's path.
 		progressbar.OptionSetMaxDetailRow(1),
 	)
 	p.widest = 0
 }
@@ -314,6 +396,19 @@ func (p *progress) increment() {
 	p.lastItem = now
 }
 // setPath records the path the walk reached last, which a display on a
 // terminal shows at its next draw.
 func (p *progress) setPath(path string) {
 	if p == nil {
 		return
 	}
 	p.mu.Lock()
 	defer p.mu.Unlock()
 	p.path = path
 }
 // warnf prints a one-line warning to stderr without corrupting the
 // display. The whole message is escaped like a report's path columns,
 // so a path holding a newline cannot split the warning.
@@ -327,11 +422,9 @@ func (p *progress) warnf(format string, args ...any) {
 	p.mu.Lock()
 	defer p.mu.Unlock()
-	if p.bar != nil {
+	// The warning takes the display's line; the next draw shows the
-		// The warning takes the display's line; the next draw shows
+	// display again, on the line below.
-		// the display again, on the line below.
+	p.clear()
 		_ = p.bar.Clear()
 	}
 	fmt.Fprintln(os.Stderr, msg)
 }
@@ -392,9 +485,7 @@ func (w *progressWriter) Flush() error {
 		w.p.mu.Lock()
 		defer w.p.mu.Unlock()
-		if w.p.bar != nil {
+		w.p.clear()
 			_ = w.p.bar.Clear()
 		}
 	}
 	_, err := w.out.Write(w.buf)
@@ -414,6 +505,13 @@ func (p *progress) finish() {
 	close(p.stop)
 	<-p.done
 	// The walk's path is only for someone watching the walk. Its line is
 	// erased, and the next phase is drawn on it.
 	p.mu.Lock()
 	p.clear()
 	p.path = ""
 	p.mu.Unlock()
 	p.draw()
 	if p.width != nil {
@@ -6,6 +6,7 @@ import (
 	"math"
 	"os"
 	"path/filepath"
 	"regexp"
 	"slices"
 	"strings"
 	"sync"
@@ -1138,3 +1139,164 @@ func TestWarningAfterLastItemKeepsBar(t *testing.T) {
 		t.Errorf("terminal shows %q, want a count of 2 of 2", shown)
 	}
 }
 func TestCutToColumns(t *testing.T) {
 	t.Parallel()
 	cases := []struct {
 		s       string
 		columns int
 		want    string
 	}{
 		{"/srv/a", 10, "/srv/a"},
 		{"/srv/photos", 8, "/srv/pho"},
 		// Each of these two fullwidth letters takes two columns.
 		{"/ＡＢ/a", 4, "/Ａ"},
 		{"/ＡＢ/a", 5, "/ＡＢ"},
 		// An accent that combines with the letter before stays with it.
 		{"/café/a", 5, "/café"},
 		{"/srv", 0, ""},
 	}
 	for _, tc := range cases {
 		if got := cutToColumns(tc.s, tc.columns); got != tc.want {
 			t.Errorf("cutToColumns(%q, %d) = %q, want %q",
 				tc.s, tc.columns, got, tc.want)
 		}
 	}
 }
 func TestEscapeControlChars(t *testing.T) {
 	t.Parallel()
 	cases := map[string]string{
 		"/srv/music":    "/srv/music",
 		"/a\x1b[2Jb":    `/a\x1b[2Jb`,
 		"/a\x00\a\x7fb": `/a\x00\x07\x7fb`,
 		// U+009B takes two bytes in UTF-8.
 		"/a\u009b2Jb": `/a\x9b2Jb`,
 		// Byte 0x9b alone is not valid UTF-8. A terminal not in UTF-8
 		// mode acts on it, as on every byte from 0x80 to 0x9f.
 		"/a\x9b2Jb":       `/a\x9b2Jb`,
 		"/a\x80\x9f\xa0b": `/a\x80\x9f` + "\xa0b",
 		// In ě, which is c4 9b in UTF-8, byte 0x9b is part of a valid
 		// character.
 		"/aě2Jb":          "/aě2Jb",
 		"/café/ＡＢ":        "/café/ＡＢ",
 		"/latin1-caf\xe9": "/latin1-caf\xe9",
 	}
 	for in, want := range cases {
 		if got := escapeControlChars(in); got != want {
 			t.Errorf("escapeControlChars(%q) = %q, want %q", in, got, want)
 		}
 	}
 }
 // pathLines returns the text of each line the library wrote below a
 // display's line. It writes one as an erase to the end of the line, a
 // carriage return, the text and a newline.
 func pathLines(out string) []string {
 	matches := regexp.MustCompile("\x1b\\[K\r([^\n]*)\n").
 		FindAllStringSubmatch(out, -1)
 	lines := make([]string, 0, len(matches))
 	for _, m := range matches {
 		lines = append(lines, m[1])
 	}
 	return lines
 }
 // TestTerminalWalkShowsPathBelow checks that the walk's display on a
 // terminal 30 columns wide shows the path it reached last on the line
 // below, cut to 29 columns. That line is erased before a warning is
 // printed, and again when the walk ends, so the next phase is drawn on
 // an empty line.
 //
 //nolint:paralleltest // captureStderr replaces the process-wide os.Stderr
 func TestTerminalWalkShowsPathBelow(t *testing.T) {
 	stderr := captureStderr(t)
 	p := startProgress(progressParams{
 		label: scanPhase("walk"), unit: scanUnit, total: -1,
 	}, func() int { return 30 }, testRedraw, time.Now)
 	const shown = "/srv/photos/2026/holiday/beac"
 	p.setPath("/srv/photos/2026/holiday/beach.jpg")
 	p.increment()
 	awaitOutput(t, stderr, shown, 1)
 	p.warnf("warning")
 	before, _, _ := strings.Cut(stderr(), "warning")
 	if lines := pathLines(before); lines[len(lines)-1] != "" {
 		t.Errorf("line below shows %q as the warning is printed, want it "+
 			"empty", lines[len(lines)-1])
 	}
 	// Drawn again below the warning.
 	awaitOutput(t, stderr, shown, strings.Count(before, shown)+1)
 	p.finish()
 	lines := pathLines(stderr())
 	if !slices.Contains(lines, shown) {
 		t.Errorf("lines below the display = %q, want %q among them",
 			lines, shown)
 	}
 	if last := lines[len(lines)-1]; last != "" {
 		t.Errorf("line below the display shows %q after the walk, want it "+
 			"empty", last)
 	}
 }
 // TestTerminalWalkEscapesControlChars checks that a walked path holding
 // escape characters, which would clear the screen and set the window
 // title, puts none on the line below the walk's display. The line shows
 // each control character written out, as \x1b.
 //
 //nolint:paralleltest // captureStderr replaces the process-wide os.Stderr
 func TestTerminalWalkEscapesControlChars(t *testing.T) {
 	stderr := captureStderr(t)
 	p := startProgress(progressParams{
 		label: scanPhase("walk"), unit: scanUnit, total: -1,
 	}, func() int { return 80 }, testRedraw, time.Now)
 	p.setPath("/srv/\x1b[2J\x1b]0;title\a/beach.jpg")
 	p.increment()
 	awaitOutput(t, stderr, "beach.jpg", 1)
 	p.finish()
 	lines := pathLines(stderr())
 	for _, line := range lines {
 		if strings.Contains(line, "\x1b") {
 			t.Errorf("line below the display = %q, want no escape "+
 				"character", line)
 		}
 	}
 	const shown = `/srv/\x1b[2J\x1b]0;title\x07/beach.jpg`
 	if !slices.Contains(lines, shown) {
 		t.Errorf("lines below the display = %q, want %q among them",
 			lines, shown)
 	}
 }
 // TestPlainWalkShowsNoPath checks that the walk's display prints no path
 // when stderr is not a terminal.
 //
 //nolint:paralleltest // captureStderr replaces the process-wide os.Stderr
 func TestPlainWalkShowsNoPath(t *testing.T) {
 	stderr := captureStderr(t)
 	p := startProgress(progressParams{
 		label: scanPhase("walk"), unit: scanUnit, total: -1,
 	}, nil, testRedraw, time.Now)
 	p.setPath("/srv/a")
 	p.increment()
 	p.finish()
 	if strings.Contains(stderr(), "/srv/a") {
 		t.Errorf("stderr = %q, want no path", stderr())
 	}
 }
@@ -98,17 +98,16 @@ func scanPhase(name string) string {
 // runs, and the lock is released after it. When ctx is cancelled, as by
 // the SIGINT or SIGTERM that interruptContext catches, the scan keeps
 // what it has hashed (see syncScan), prints how many files its walk
-// reached, and returns errInterrupted. workers must be at least 1; the
+// reached, and returns errInterrupted. opts.workers must be at least 1;
-// scan command rejects anything less. Before the lock is taken, the
+// the scan and dwim commands reject anything less. Before the lock is
-// scan lists the filesystems that are not persistent, on which the walk
+// taken, the scan lists the filesystems that are not persistent, on
-// records nothing; unless noDefaultExcludes is set, the walk does not
+// which the walk records nothing; unless opts.noDefaultExcludes is set,
-// enter the default excludes either. The walk neither enters nor
+// the walk does not enter the default excludes either. The walk neither
-// records the paths in excludePaths, the --exclude values; an operand
+// enters nor records the paths in opts.excludePaths, the --exclude
-// at or below one is a fatal error. Once the database is open, the scan
+// values; an operand at or below one is a fatal error. Once the
-// notes its files, which the walk passes over.
+// database is open, the scan notes its files, which the walk passes
-func runScan(ctx context.Context, roots []string, workers int,
+// over.
-	oneFS, noDefaultExcludes bool, excludePaths []string,
+func runScan(ctx context.Context, roots []string, opts scanOptions) error {
 ) error {
 	dbPath, source, err := databasePath()
 	if err != nil {
 		return err
@@ -123,7 +122,7 @@ func runScan(ctx context.Context, roots []string, workers int,
 	var rules walkRules
-	rules.excludePaths, err = excludePathInodes(excludePaths)
+	rules.excludePaths, err = excludePathInodes(opts.excludePaths)
 	if err != nil {
 		return fmt.Errorf("--exclude: %w", err)
 	}
@@ -138,7 +137,7 @@ func runScan(ctx context.Context, roots []string, workers int,
 		return fmt.Errorf("list the mounted filesystems: %w", err)
 	}
-	if !noDefaultExcludes {
+	if !opts.noDefaultExcludes {
 		rules.defaultExcludes = defaultExcludes(runtime.GOOS)
 	}
@@ -167,7 +166,7 @@ func runScan(ctx context.Context, roots []string, workers int,
 		return err
 	}
-	st, err := syncScan(ctx, db, roots, workers, oneFS, rules)
+	st, err := syncScan(ctx, db, roots, opts.workers, opts.oneFS, rules)
 	if errors.Is(err, context.Canceled) {
 		return interrupted(st.walked)
 	}
@@ -563,6 +562,7 @@ func (s *scanState) walkPhase(events <-chan walkEvent, roots []string) {
 		s.st.walked++
 		prog.setPath(ev.rec.path)
 		prog.increment()
 		old, ok := s.existing[ev.rec.path]
@@ -2196,7 +2196,7 @@ func TestScanHashWriteFailureUnwindsPool(t *testing.T) {
 	var stderr bytes.Buffer
 	code := run([]string{
-		cmdScan, "--workers", strconv.Itoa(hashLeakWorkers), dir,
+		cmdScan, workersFlag, strconv.Itoa(hashLeakWorkers), dir,
 	}, io.Discard, &stderr)
 	if code != exitFatal {
 		t.Fatalf("run(scan) = %d, want %d; stderr: %s",
Author	SHA1	Message	Date
clawbot	be47255598	Show the walk's path on the line below its display (closes #160 ) check / check (push) Successful in 1m45s Details On a terminal, each draw of the walk shows the path of the last file it found on the line below, cut short before the last column with wide characters counted as two columns. The progressbar library's detail row draws it. Control characters in the path are written out, as \t or \x1b, so that the terminal does not act on them. The line is erased before a warning and when the walk ends, so the next phase is drawn on it. Nothing changes when stderr is not a terminal. github.com/rivo/uniseg, already in the module graph through the progressbar library, becomes a direct dependency for the column count. Model: opus-5-5	2026-11-11 08:22:51 +00:00
clawbot	3732ecef1f	TODO.md: keep only open work (closes #167 ) (#180 ) check / check (push) Canceled after 0s Details	2026-11-11 09:07:13 +01:00
clawbot	a9ab6124ae	dwim: take the scan flags (closes #162 ) (#193 ) check / check (push) Canceled after 0s Details	2026-11-11 08:37:18 +01:00
clawbot	db56fd0e4c	Say in --help where the database is and what each report prints (closes #177 ) (#189 ) check / check (push) Canceled after 0s Details	2026-11-11 07:22:28 +01:00