install.sh

   1 #!/bin/sh
   2 #
   3 # Written by Rich Felker, originally as part of musl libc.
   4 # Multi-licensed under MIT, 0BSD, and CC0.
   5 #
   6 # This is an actually-safe install command which installs the new
   7 # file atomically in the new location, rather than overwriting
   8 # existing files.
   9 #
  10
  11 usage() {
  12 printf "usage: %s [-D] [-l] [-m mode] src dest\n" "$0" 1>&2
  13 exit 1
  14 }
  15
  16 mkdirp=
  17 symlink=
  18 mode=755
  19
  20 while getopts Dlm: name ; do
  21 case "$name" in
  22 D) mkdirp=yes ;;
  23 l) symlink=yes ;;
  24 m) mode=$OPTARG ;;
  25 ?) usage ;;
  26 esac
  27 done
  28 shift $(($OPTIND - 1))
  29
  30 test "$#" -eq 2 || usage
  31 src=$1
  32 dst=$2
  33 tmp="$dst.tmp.$$"
  34
  35 case "$dst" in
  36 */) printf "%s: %s ends in /\n", "$0" "$dst" 1>&2 ; exit 1 ;;
  37 esac
  38
  39 set -C
  40 set -e
  41
  42 if test "$mkdirp" ; then
  43 umask 022
  44 case "$2" in
  45 */*) mkdir -p "${dst%/*}" ;;
  46 esac
  47 fi
  48
  49 trap 'rm -f "$tmp"' EXIT INT QUIT TERM HUP
  50
  51 umask 077
  52
  53 if test "$symlink" ; then
  54 ln -s "$1" "$tmp"
  55 else
  56 cat < "$1" > "$tmp"
  57 chmod "$mode" "$tmp"
  58 fi
  59
  60 mv -f "$tmp" "$2"
  61 test -d "$2" && {
  62 rm -f "$2/$tmp"
  63 printf "%s: %s is a directory\n" "$0" "$dst" 1>&2
  64 exit 1
  65 }
  66
  67 exit 0