File: same.sh
   1 #!/bin/sh
   2 
   3 # The MIT License (MIT)
   4 #
   5 # Copyright (c) 2026 pacman64
   6 #
   7 # Permission is hereby granted, free of charge, to any person obtaining a copy
   8 # of this software and associated documentation files (the "Software"), to deal
   9 # in the Software without restriction, including without limitation the rights
  10 # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11 # copies of the Software, and to permit persons to whom the Software is
  12 # furnished to do so, subject to the following conditions:
  13 #
  14 # The above copyright notice and this permission notice shall be included in
  15 # all copies or substantial portions of the Software.
  16 #
  17 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18 # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19 # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  20 # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21 # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  23 # SOFTWARE.
  24 
  25 
  26 # same [options...] [file 1] [file 2]
  27 #
  28 #
  29 # Check if 2 files have the same contents. Output is emitted only for errors,
  30 # and only on the standard error, if so.
  31 #
  32 # This tool is used for its return code, which is 0 when the files have the
  33 # same contents, 1 when they don't, or 2 when not given exactly 2 files to
  34 # compare, or if either file isn't found.
  35 #
  36 # The options are, available both in single and double-dash versions
  37 #
  38 #   -h, -help    show this help message
  39 
  40 
  41 case "$1" in
  42     -h|--h|-help|--help)
  43         awk '/^# +same /, /^$/ { gsub(/^# ?/, ""); print }' "$0"
  44         exit 0
  45     ;;
  46 
  47     -) ;;
  48 
  49     --) shift ;;
  50 
  51     -*)
  52         printf "%s: unsupported option %s\n" "$0" "$1" >&2
  53         exit 2
  54     ;;
  55 esac
  56 
  57 if [ $# -ne 2 ]; then
  58     printf "given %d files, instead of 2\n" "$#" >&2
  59     exit 2
  60 fi
  61 
  62 if [ "$1" = '-' ] && [ "$2" = '-' ]; then
  63     exit 0
  64 fi
  65 
  66 if [ "$1" = "$2" ]; then
  67     if [ -e "$1" ]; then
  68         exit 0
  69     else
  70         printf "file named '%s' not found\n" "$1" >&2
  71         exit 2
  72     fi
  73 fi
  74 
  75 if [ "$1" != '-' ] && [ ! -e "$1" ]; then
  76     printf "file named '%s' not found\n" "$1" >&2
  77     exit 2
  78 fi
  79 if [ "$2" != '-' ] && [ ! -e "$2" ]; then
  80     printf "file named '%s' not found\n" "$2" >&2
  81     exit 2
  82 fi
  83 
  84 diff -q "$1" "$2" > /dev/null