bin/git-amend

   1 #!/bin/sh -e
   2 # Usage: git-amend <commit>
   3 # Amend changes staged in the index to <commit>, or edit commit message if
   4 # no changes are currently staged. Modifications not staged are stashed and
   5 # then reapplied once the amend and rebase operations are complete.
   6 #
   7 # This command rewrites history. Do not run it after <commit> or its
   8 # decendants have been published to the world.
   9 #
  10 # This version in POSIX sh by Ryan Tomayko <tomayko.com/about>
  11 #
  12 # Based on Mislav's bash version here:
  13 # http://gist.github.com/278825
  14
  15 # NOTE removed check for staged files, since sometimes I just
  16 # want to change the commit message.
  17
  18 TARGET="$1"
  19 BRANCH=$(git name-rev HEAD | cut -d' ' -f2)
  20
  21 test -z "$TARGET" && {
  22   echo "$(basename $0): you must specify the target commit" 1>&2
  23   exit 1
  24 }
  25
  26 # if there are local work tree modifications, stash those off leaving
  27 # the index for amending to the target commit
  28 DIRTY=0
  29 if ! git diff-files --quiet --ignore-submodules --; then
  30   DIRTY=1
  31 fi
  32 test $DIRTY -eq 1 && git stash save -q --keep-index git-amend
  33 # always restore from stash before exiting
  34 test $DIRTY -eq 1 && trap 'git stash pop -q stash@{0} 2>/dev/null' EXIT
  35
  36 # go back in history
  37 git checkout -q "$TARGET" || {
  38   echo "$(basename $0): changes didn't apply cleanly" 1>&2
  39   exit 1
  40 }
  41
  42 # amend the commit. this opens your editor
  43 git commit -v --amend
  44
  45 # apply the remaining commits on this branch
  46 git rebase --onto HEAD "$TARGET" "$BRANCH"