Bash
Bash trap: Clean Up Temp Files and Locks on Exit
Temp files and stale locks left behind by failed scripts are avoidable. Tested trap patterns for EXIT, INT, TERM and ERR, plus mkdir and flock locks.
Topic
files
Bash
Read a File Line by Line in Bash (the Right Way)
while IFS= read -r line is the correct loop, but the last line, pipes, commands that read stdin and Windows line endings each have a trap. Here they are, tested.
Linux
rsync Recipes: Trailing Slashes, --delete and Filters
One missing slash nests a directory. One empty source wipes a backup. Tested rsync recipes for mirroring, filtering, verifying and copying over SSH.
Linux
Docker Volumes vs Bind Mounts, and the File Ownership Trap
Why a volume shows the image's files and a bind mount hides them, and how a root container leaves files your own user cannot edit or delete. Four tested fixes.
Programming
Python venv in Practice: Create, Use and Rebuild
How I use python -m venv on servers and laptops: one environment per project, pinned requirements, no activation in cron, and why .venv never goes into Git.
Bash
__pgrepf() in Bash: pgrep -f Using Only /proc
Find processes by their full command line in pure Bash by reading /proc/PID/cmdline, with the NUL bytes handled properly and the 2009 bugs fixed.
Bash
emptydir() in Bash: Check Whether a Directory Is Empty
Test whether a directory is empty in pure Bash with nullglob and dotglob, handle hidden and unreadable directories, and know when find -quit is faster.