A One-Liner to Prefix Filenames with Their Last Modified Date

One-Liner

for f in *; do [ -f "$f" ] && mv "$f" "$(stat -f '%Sm' -t '%Y%m%dT%H%M%S' "$f")_$f"; done

For each file in the current directory, this retrieves the last modified date using stat and renames the file by prepending a prefix in the format YYYYMMDDTHHmmSS_.

On Linux, the stat options differ.

for f in *; do [ -f "$f" ] && mv "$f" "$(stat -c '%Y' "$f" | xargs -I{} date -d @{} '+%Y%m%dT%H%M%S')_$f"; done

Example

$ ls
bar.md  baz.md  foo.md

$ for f in *; do [ -f "$f" ] && mv "$f" "$(stat -f '%Sm' -t '%Y%m%dT%H%M%S' "$f")_$f"; done

$ ls
20260218T143012_bar.md  20260220T091530_baz.md  20260215T220845_foo.md

You can now tell at a glance which files are the most recent.

What I Used This For

The plan files that Claude Code’s Plan agent generates in .claude/plans/ use random UUIDs in their filenames and contain no information about when they were last modified. As plan files accumulate, it becomes impossible to tell which ones are the most recent. I solved this by batch-renaming them with the one-liner above.