If you start a commit message with “squash!”, git’s interactive rebase will automatically mark that commit to be squashed.

Riveting example

$ git log

commit f3c9e55396c2294e672de91d1d26f0949f05ce53
Author: Chad Knight <chadrknight@gmail.com>
Date:   Tue Aug 30 21:24:42 2016 -0500

    squash! autosquash post
    
    - add source

commit 66240d95cacca5f7a5b82d2bf4e9042debdbd85e
Author: Chad Knight <chadrknight@gmail.com>
Date:   Tue Aug 30 21:23:47 2016 -0500

    squash! autosquash post
    
    - add workflow steps

commit 3dccb7c58937977fd8563cf5e145e17f480b9d28
Author: Chad Knight <chadrknight@gmail.com>
Date:   Tue Aug 30 21:18:31 2016 -0500

    autosquash post

$ git rebase master -i --autosquash

pick 3dccb7c autosquash post
squash 66240d9 squash! autosquash post
squash f3c9e55 squash! autosquash post

# Rebase 1ee84ec..f3c9e55 onto 1ee84ec (3 command(s))
#
# Commands:
# p, pick = use commit
# r, reword = use commit, but edit the commit message
# e, edit = use commit, but stop for amending
# s, squash = use commit, but meld into previous commit
# f, fixup = like "squash", but discard this commit's log message
# x, exec = run command (the rest of the line) using shell
# d, drop = remove commit
#
# These lines can be re-ordered; they are executed from top to bottom.
#
# If you remove a line here THAT COMMIT WILL BE LOST.
#
# However, if you remove everything, the rebase will be aborted.
#
# Note that empty commits are commented out

[[ remove all the extra lines from the final message ]]

Rebasing (2/3)

Rebasing (3/3)

[detached HEAD 901f6df] autosquash post
 Date: Tue Aug 30 21:18:31 2016 -0500
 1 file changed, 27 insertions(+)
 create mode 100644 til/_posts/2016-08-30-autosquash.md
Successfully rebased and updated refs/heads/autosquash.

$ git log

commit 901f6df8c3aa74e611f5d33fb4188354fa1784fe
Author: Chad Knight <chadrknight@gmail.com>
Date:   Tue Aug 30 21:18:31 2016 -0500

    autosquash post
    
    - add workflow steps
    - add source

Add an alias

git config --global alias.squash "rebase master -i --autosquash"

New workflow

  1. Branch off master
  2. Make your first set of changes
  3. Commit with the title of your eventual PR
  4. Make more changes
  5. Commit with “squash! “ and the original title again, with details about the commit below
  6. Repeat as needed
  7. Merge in updated master as needed
  8. git squash
  9. Push and PR

Fixup

You can also use “fixup!” if you want to automatically drop the message from that commit while squashing.

SOURCE: git rebase --help