File: dedup.sh
   1 #!/bin/sh
   2 
   3 # The MIT License (MIT)
   4 #
   5 # Copyright © 2020-2025 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 # dedup [filepaths...]
  27 #
  28 # Deduplicate lines, ensuring each unique input line appears only once on the
  29 # output. Unlike the standard cmd-line app `uniq`, which only works correctly
  30 # when given sorted lines, this tool works correctly without any scrambling.
  31 
  32 
  33 case "$1" in
  34     -h|--h|-help|--help)
  35         awk '/^# +dedup /, /^$/ { gsub(/^# ?/, ""); print }' "$0"
  36         exit 0
  37     ;;
  38 esac
  39 
  40 [ "$1" = "--" ] && shift
  41 
  42 command='awk'
  43 if [ -p /dev/stdout ] || [ -t 1 ]; then
  44     command='stdbuf -oL awk'
  45 fi
  46 
  47 # show all non-existing files given
  48 failed=0
  49 for arg in "$@"; do
  50     if [ "${arg}" = "-" ]; then
  51         continue
  52     fi
  53     if [ ! -e "${arg}" ]; then
  54         printf "no file named \"%s\"\n" "${arg}" > /dev/stderr
  55         failed=1
  56     fi
  57 done
  58 
  59 if [ "${failed}" -gt 0 ]; then
  60     exit 2
  61 fi
  62 
  63 ${command} '
  64     BEGIN { for (i = 1; i < ARGC; i++) if (files[ARGV[i]]++) delete ARGV[i] }
  65     !c[$0]++
  66 ' "$@"