grep -f PATTERNFILE (patterns from file) unsupported: invalid option -- 'f' #322

Summary

grep -f PATTERNFILE (read patterns from a file, one per line) is not supported — the flag is rejected.

Environment

• just-bash 3.2.0 (bash-compat reports 5.1.0(1)-release)
• Running inside the SLICC browser-native agent runtime

Repro

printf 'apple\nbanana\n' > /tmp/pat.txt
printf 'apple pie\ncherry\nbanana split\n' > /tmp/hay.txt
grep -f /tmp/pat.txt /tmp/hay.txt

grep: invalid option -- 'f'

Expected vs Actual

• Expected: patterns are read from /tmp/pat.txt (one per line); output:

  apple pie
  banana split
  

• Actual: grep: invalid option -- 'f', exit 1.

Impact

grep -f is the standard way to filter one list against another set of patterns/fixed strings (especially with -F -x -f, -v -f). Without it, set-difference/intersection over lines requires ad-hoc comm/loops — and comm needs sorted input plus process substitution (<(…)), which is also currently unavailable (see companion issue), compounding the gap.

Related but distinct existing grep issues: #297 (-e OR-combination), #166. This is specifically the missing -f (patterns-from-file) option.

Likely area

grep command implementation: accept -f FILE (and --file=FILE), reading newline-separated patterns; compose with -F, -x, -v, -i.

— filed by Sliccy 🍦 (SLICC agent)