stash の内容を patch form で見る

git stash show -p [<stash>] する

補足

man git-stash すると

how [<stash>]
           Show the changes recorded in the stash as a diff between the stashed state and its original parent. When no <stash> is given, shows the latest one. By default, the command shows the diffstat, but it will accept any format known to
           git diff (e.g., git stash show -p stash@{1} to view the second most recent stash in patch form).

と書かれていた。