diff --git a/README.markdown b/README.markdown
index 2884761..a882428 100644
--- a/README.markdown
+++ b/README.markdown
@@ -17,7 +17,26 @@ This outputs the config file, including the
 rpc user password (either from `BITCOIND_RPCPASSWORD` or randomly
 generated) to the logs on startup.
 
+# Security
+
+This container logs the rpc password into the container's logfiles.
+
 # Versions
 
 * sneak/bitcoind:latest -> bitcoind master
-* sneak/bitcoind:0.12.0 -> bitcoind v0.12.0
+* sneak/bitcoind:v0.18.1 -> bitcoind v0.18.1
+
+# Usage
+
+```
+docker run \
+        --name bitcoind \
+        -v /storage/bitcoin/bitcoind:/var/lib/bitcoind \
+        --env BITCOIND_RPCUSER=username \
+        --env BITCOIND_RPCPASSWORD=supersecret \
+        -p 8333:8333 \
+        -p 8332:8332 \
+        -d sneak/bitcoind:v0.18.1
+
+docker logs -f bitcoind
+```
diff --git a/bitcoind.run b/bitcoind.run
index 745a38d..640ba46 100644
--- a/bitcoind.run
+++ b/bitcoind.run
@@ -3,7 +3,7 @@
 export HOME="/var/lib/bitcoind"
 
 # gen random pw for rpc server
-RANDOMPW=$(dd if=/dev/urandom bs=10 count=1 status=none | shasum | cut -b 1-20)
+RANDOMPW=$(tr -dc 'a-f0-9' < /dev/urandom | head -c20)
 
 cat <<EOF > $HOME/bitcoin.conf
 rpcuser=${BITCOIND_RPCUSER:-rpcuser}