Two problems, both data loss.
It gzipped any *.log older than the threshold. gzip writes the .gz and
unlinks the original, so a daemon holding that file open keeps writing
to an unlinked inode and those writes become unreachable -- the exact
failure real logrotate avoids with copytruncate or a postrotate signal.
We can do neither from here, so files currently held open are now
skipped and left for logrotate, and the run says so. If lsof is missing
the check cannot run, and that is reported rather than assumed safe.
It also deleted every .gz older than a hardcoded 90 days, on every run,
with no flag, no dry-run and no confirmation -- destroying archives on
any host with longer retention. Deletion is now opt-in via --purge-days,
prints what it will remove, and needs an interactive confirmation or
--yes. Without a tty and without --yes it refuses instead of proceeding.
Adds --dry-run, --days, -h, and set -euo pipefail. A bare numeric first
argument still works, so existing `log_rotate.sh 14` callers and cron
entries are unaffected.
Verified against a fixture directory: old logs compressed and recent
ones left alone, archives surviving when --purge-days is absent, purge
refusing non-interactively without --yes, and a file held open by a
running process skipped rather than compressed.
jcoffey-dev
LINUXexpert.org