Voir fichier à un commit :
git show HASH:path/to/file

Hash du commit initial :
git rev-list --max-parents=0 HEAD

Voir liste fichiers modifiés entre 2 commits :
git diff --name-only SHA1 SHA2
git log --name-status --oneline HEAD~6..HEAD
git log --name-status --oneline HEAD~6..HEAD |grep -vP '^\S[^\s]'|sort|uniq

Voir modif sur un fichier entre 2 commits :
git diff SHA1 SHA2 main.c

Trouver l'ancetre commun le plus vieux
git config --global alias.oldest-ancestor '!bash -c '\''diff -u <(git rev-list --first-parent "${1:-master}") <(git rev-list --first-parent "${2:-HEAD}") | sed -ne "s/^ //p" | head -1'\'' -'
git oldest-ancestor

git rebase -i [HASH parent]

man -7 gitrevisions

HEAD
HEAD~1 HEAD^ HEAD^1
HEAD~2 HEAD^2 HEAD~1^
HEAD~3

10:10 V /tmp/git_test [master L|V]
$ git lola

• 52f73ef (HEAD -> refs/heads/master) Merge branch 'toto'
  |\
  | * 2f39200 (refs/heads/toto) commit on toto
• | d581320 Commit on master
  |/
• eae368a first commit
  10:10 V /tmp/git_test [master L|V]
  $ git log --name-status --oneline eae368a..52f73ef
  52f73ef Merge branch 'toto'
  d581320 Commit on master
  A tata
  2f39200 commit on toto
  A b