How to quickly squash git commits

Three-step process to squash git commits.

First step

Check current branch name.

$ git branch --show-current

SITE-5000

Display commits.

$ git log --oneline -6

6ce8233 (HEAD -> SITE-5000) Update on branch SITE-5000 #4
6a25fe3 Update on branch SITE-5000 #3
30885c7 Update on branch SITE-5000 #2
df9c454 Update on branch SITE-5000 #1
8ccf509 (origin/SITE-4999, SITE-4999) Update on branch SITE-4999 #1
605b30b (origin/main, main) first commit

Count commits on the current branch that is not tracked remotely.

$ git rev-list HEAD --not --remotes=*/* --count

Things are different when the current branch is already tracked remotely.

$ git log --oneline -6

6ce8233 (HEAD -> SITE-5000, origin/SITE-5000) Update on branch SITE-5000 #4
6a25fe3 Update on branch SITE-5000 #3
30885c7 Update on branch SITE-5000 #2
df9c454 Update on branch SITE-5000 #1
8ccf509 (origin/SITE-4999, SITE-4999) Update on branch SITE-4999 #1
605b30b (origin/main, main) first commit

Determine the parent branch.

$ git show-branch --topo-order

! [SITE-4999] Update on branch SITE-4999 #1
 * [SITE-5000] Update on branch SITE-5000 #4
  ! [main] first commit
---
 *  [SITE-5000] Update on branch SITE-5000 #4
 *  [SITE-5000^] Update on branch SITE-5000 #3
 *  [SITE-5000~2] Update on branch SITE-5000 #2
 *  [SITE-5000~3] Update on branch SITE-5000 #1
+*  [SITE-4999] Update on branch SITE-4999 #1
+*+ [main] first commit

Count commits on the current branch.

$ git rev-list HEAD --not --remotes=*/SITE-4999 --count

Second step

Reset the current HEAD to specific point in time you got earlier.

$ git reset --soft HEAD~4

Commit all changes as a single commit.

$ git commit -m "All-in-one update"

Alternatively, use an interactive mode.

$ git rebase --interactive HEAD~4

Third step

Push changes to the repository.

Additional notes

Simplest possible use case.

$ git reset --soft HEAD~$(git rev-list HEAD --not --remotes=*/main --count)

$ git commit -m "SITE-5555 Update blog post"

$ git push --force