ga-find-exist

   1 #!/bin/sh
   2
   3 #==============================================================================
   4 # ga-find-exist
   5 # File ID: b3bc789e-fb2a-11e7-a332-f74d993421b0
   6 #
   7 # [Description]
   8 #
   9 # Author: Øyvind A. Holm <sunny@sunbase.org>
  10 # License: GNU General Public License version 2 or later.
  11 #==============================================================================
  12
  13 progname=ga-find-exist
  14 VERSION=0.1.0
  15
  16 opt_help=0
  17 opt_quiet=0
  18 opt_verbose=0
  19 while test -n "$1"; do
  20         case "$1" in
  21         -h|--help) opt_help=1; shift ;;
  22         -q|--quiet) opt_quiet=$(($opt_quiet + 1)); shift ;;
  23         -v|--verbose) opt_verbose=$(($opt_verbose + 1)); shift ;;
  24         --version) echo $progname $VERSION; exit 0 ;;
  25         --) shift; break ;;
  26         *)
  27                 if printf '%s\n' "$1" | grep -q ^-; then
  28                         echo "$progname: $1: Unknown option" >&2
  29                         exit 1
  30                 else
  31                         break
  32                 fi
  33         break ;;
  34         esac
  35 done
  36 opt_verbose=$(($opt_verbose - $opt_quiet))
  37
  38 if test "$opt_help" = "1"; then
  39         exname=big.iso
  40
  41         test $opt_verbose -gt 0 && { echo; echo $progname $VERSION; }
  42         cat <<END
  43
  44 Usage: $progname [options] FILENAME
  45
  46 Go back in time in Git for a specific filename until FILENAME exists and
  47 is not a broken symlink. Checks all earlier revisions where FILENAME was
  48 modified. Abort if the git command fails.
  49
  50 Very suitable for git-annex, but can also be used with regular git. In
  51 git-annex, it keeps scanning the history backwards until the symlink
  52 isn't broken anymore. Can be used to find a reference file for rsync
  53 transfers. If the files share common data, the transfer speed can be
  54 increased dramatically. For example, transfer time for upgraded isofs
  55 images can be reduced because not all files have changed, especially if
  56 the files are stored in the same order as the previous version.
  57
  58   \$ $progname $exname # HEAD becomes detached if the file didn't exist
  59   \$ git annex edit $exname
  60   \$ rsync -avzL --progress user@remotehost:/path/to/$exname $exname
  61   \$ git annex reinject --known $exname
  62   \$ git checkout -f $exname # Was deleted by git annex reinject
  63   \$ git checkout master
  64
  65 Returns 0 if FILENAME exists or it was found in the Git history.
  66 Returns 1 if the git command failed or the file wasn't found.
  67
  68 Options:
  69
  70   -h, --help
  71     Show this help.
  72   -q, --quiet
  73     Be more quiet. Can be repeated to increase silence.
  74   -v, --verbose
  75     Increase level of verbosity. Can be repeated.
  76   --version
  77     Print version information.
  78
  79 END
  80         exit 0
  81 fi
  82
  83 file="$1"
  84
  85 if test -z "$file"; then
  86         echo $progname: No file specified >&2
  87         exit 1
  88 fi
  89
  90 test -e "$file" && exit 0
  91
  92 shas="$(git log --format=%h -- "$file")"
  93
  94 if test -z "$shas"; then
  95         echo $progname: $file: File not found in the Git history >&2
  96         exit 1
  97 fi
  98
  99 test $opt_verbose -ge 1 && echo $progname: Checking revisions $shas >&2
 100
 101 for s in $shas; do
 102         git checkout $s || exit 1
 103         test -e "$file" && exit 0
 104 done
 105
 106 # vim: set ts=8 sw=8 sts=8 noet fo+=w tw=79 fenc=UTF-8 :