user-tools/chshebang

   1 #!/bin/bash
   2
   3 true <<EOF
   4 =pod
   5
   6 =head1 NAME
   7
   8 chshebang - Change a script's default interpreter
   9
  10 =cut
  11
  12 EOF
  13
  14
  15 force=0
  16 insert=0
  17 dummy=0
  18 NL=$'\n'
  19
  20 while [ -n "$1" ]; do
  21         case "$1" in
  22         -h|--help)
  23                 echo "Usage: $0 [-h|--help] [-f|--force] [-i|--insert] [-d|--dummy] <INTERPRETER> <FILES> ...
  24   -f   force replace 1st line with INTERPRETER, even if it does not start \`#!' signature
  25   -i   insert, instead of replace
  26   -d   disable intelligent path preparation
  27   INTERPRETER   basename or full path of new interpreter, leading \`#!' signature is implicite
  28                 examplpes: /usr/bin/awk, bash, #!/bin/sh
  29   FILES         files to modify"
  30                 exit 0;;
  31         -f|--force)
  32                 force=1;;
  33         -i|--insert)
  34                 insert=1;;
  35         -d|--dummy)
  36                 dummy=1;;
  37         -*)     echo "Unknown option: $1" >&2
  38                 exit 1;;
  39         --)     shift
  40                 break;;
  41         *)      break;;
  42         esac
  43         shift
  44 done
  45
  46
  47 shebang=$1
  48 shift
  49
  50 if [ $dummy = 0 ]; then
  51         if [ "${shebang:0:2}" != '#!' ]; then
  52                 if [ "${shebang:0:1}" != '/' ]; then
  53                         p=`which "$shebang"`
  54                         if [ $? = 0 ]; then
  55                                 shebang=$p
  56                         else
  57                                 echo "Command not found: $shebang" >&2
  58                                 exit 2
  59                         fi
  60                 fi
  61                 shebang="#!$shebang"
  62         fi
  63 fi
  64
  65 # escape sed(1) meta chars in this order: \ , &
  66 shebang=${shebang//\\/\\\\}
  67 shebang=${shebang//,/\\,}
  68 shebang=${shebang//&/\\&}
  69
  70 if [ $insert -eq 1 ]; then
  71         for file; do
  72                 sed -n "1i$shebang${NL}p" -i "$file"
  73         done
  74
  75 elif [ $force -eq 1 ]; then
  76         for file; do
  77                 sed -n "1s,^.*\$,$shebang,;p" -i "$file"
  78         done
  79
  80 else
  81         for file; do
  82                 sed -n "1s,^#!/.*\$,$shebang,;p" -i "$file"
  83         done
  84 fi
  85