initial commit of some preliminary notes

tools/editconf.py

@@ -0,0 +1,37 @@
+#!/usr/bin/python3
+
+import sys, re
+
+# sanity check
+if len(sys.argv) < 3:
+	print("usage: python3 editconf.py /etc/file.conf NAME=VAL [NAME=VAL ...]")
+	sys.exit(1)
+
+# parse command line arguments
+filename = sys.argv[1]
+settings = sys.argv[2:]
+
+# create the new config file in memory
+found = set()
+buf = ""
+for line in open(filename):
+	for i in range(len(settings)):
+		name, val = settings[i].split("=", 1)
+		if re.match("\s*" + re.escape(name) + "\s*=", line):
+			buf += "#" + line
+			if i in found: break # we've already set the directive
+			buf += name + "=" + val + "\n"
+			found.add(i)
+			break
+	else:
+		# did not match any setting name
+		buf += line
+		
+for i in range(len(settings)):
+	if i not in found:
+		buf += settings[i] + "\n"
+
+# Write out the new file.
+with open(filename, "w") as f:
+	f.write(buf)
+	

tools/get_ubuntu_ami.py

@@ -0,0 +1,26 @@
+import sys, json, re
+
+# Arguments:
+region, version, arch, instance_type = sys.argv[1:]
+
+# Read bytes from stdin.
+dat = sys.stdin.read()
+
+# Be flexible. The Ubuntu AMI list is invalid JSON by having a comma
+# following the last element in a list.
+dat = re.sub(r",(\s*)\]", r"\1]", dat)
+
+# Parse JSON.
+dat = json.loads(dat)
+
+for item in dat["aaData"]:
+	if item[0] == region and item[2] == version and item[3] == arch and item[4] == instance_type:
+		ami_link = item[6]
+		
+		# The field comes in the form of <a href="...">ami-id</a>
+		ami_link = re.sub(r"<.*?>", "", ami_link)
+		
+		print(ami_link)
+		break
+		
+