grep — OpenBSD grep (pattern search) for AmigaOS

Original author: James Howard / Dag-Erling Smorgrav
Ported by Duncan Bowring using amiport (AI-assisted porting toolkit).
Project: https://github.com/bdgscotland/amiport

Cross-compiled with m68k-amigaos-gcc for AmigaOS 3.x (68000+).
Tested in vamos emulator and FS-UAE (Amiga 1200).

Usage:
  grep [options] pattern [file ...]

  grep hello file.txt          Search for "hello" in file.txt
  grep -i HELLO file.txt       Case-insensitive search
  grep -n pattern file.txt     Show line numbers
  grep -v pattern file.txt     Show non-matching lines
  grep -c pattern file.txt     Count matching lines
  grep -E "foo|bar" file.txt   Extended regex (alternation)
  grep -F "a.b" file.txt       Fixed string (no regex)
  grep -R pattern dir          Recursive directory search
  grep -B2 -A2 pattern file    Show 2 lines before/after match

Exit codes (Amiga-native):
  0  = match found (RETURN_OK)
  5  = no match found (RETURN_WARN)
  10 = error (RETURN_ERROR)

Note: -Z (decompress) is not supported (no zlib on AmigaOS).

Includes full source code (original POSIX and ported Amiga versions)
and PORT.md documenting every transformation applied.

 PERMSSN    UID  GID    PACKED    SIZE  RATIO METHOD CRC     STAMP          NAME
---------- ----------- ------- ------- ------ ---------- ------------ -------------
-rw-r--r--     0/0        4136    9217  44.9% -lh5- e6de Mar 22 20:33 PORT.md
-rw-r--r--     0/0        3599   16784  21.4% -lh5- 0cb4 Mar 22 20:33 TEST-REPORT.md
-rw-r--r--     0/0       34967   64840  53.9% -lh5- 2d2e Mar 22 20:33 grep
-rw-r--r--     0/0         757    1523  49.7% -lh5- d96c Mar 22 20:33 grep.readme
drwxr-xr-x     0/0           0       0 ****** -lhd- 0000 Mar 22 20:33 original/
-rw-r--r--     0/0        1194    2368  50.4% -lh5- c22f Mar 22 20:33 original/binary.c
-rw-r--r--     0/0        1895    4506  42.1% -lh5- e7d5 Mar 22 20:33 original/file.c
-rw-r--r--     0/0        4648   12933  35.9% -lh5- 30f5 Mar 22 20:33 original/grep.c
-rw-r--r--     0/0        1663    3685  45.1% -lh5- 70f1 Mar 22 20:33 original/grep.h
-rw-r--r--     0/0        1255    2450  51.2% -lh5- d7cf Mar 22 20:33 original/mmfile.c
-rw-r--r--     0/0        1289    2750  46.9% -lh5- af17 Mar 22 20:33 original/queue.c
-rw-r--r--     0/0        5559   15729  35.3% -lh5- 2efa Mar 22 20:33 original/util.c
drwxr-xr-x     0/0           0       0 ****** -lhd- 0000 Mar 22 20:33 ported/
-rw-r--r--     0/0        1211    2312  52.4% -lh5- 1dd2 Mar 22 20:33 ported/binary.c
-rw-r--r--     0/0        3195   10563  30.2% -lh5- 5b22 Mar 22 20:33 ported/compat.h
-rw-r--r--     0/0        2011    4436  45.3% -lh5- 1b90 Mar 22 20:33 ported/file.c
-rw-r--r--     0/0        6389   18706  34.2% -lh5- b962 Mar 22 20:33 ported/grep.c
-rw-r--r--     0/0        2002    4353  46.0% -lh5- 191b Mar 22 20:33 ported/grep.h
-rw-r--r--     0/0        1350    2835  47.6% -lh5- 6e12 Mar 22 20:33 ported/queue.c
-rw-r--r--     0/0        6499   18029  36.0% -lh5- c67f Mar 22 20:33 ported/util.c
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total        20 files   83619  198019  42.2%            Mar 22 23:48