使用git进行版本控制，修改最后一次提交的用户名，命令为：
git commit --amend --author=xxx就会将git最后一次提交的用户名修改为xxx。
修改最后一次commit提交信息，命令为：
git commit --amend -m "update message"就会将git最后一次commit提交信息修改为udpate message。
下面为获取git commit --amend命令的使用说明，
git commit --amend --help结果如下所示：
usage: git commit [<options>] [--] <pathspec>...
-q, --quiet suppress summary after successful commit
-v, --verbose show diff in commit message template
Commit message options
-F, --file <file> read message from file
--author <author> override author for commit
--date <date> override date for commit
-m, --message <message>
commit message
-c, --reedit-message <commit>
reuse and edit message from specified commit
-C, --reuse-message <commit>
reuse message from specified commit
--fixup <commit> use autosquash formatted message to fixup specified commit
--squash <commit> use autosquash formatted message to squash specified commit
--reset-author the commit is authored by me now (used with -C/-c/--amend)
-s, --signoff add Signed-off-by:
-t, --template <file>
use specified template file
-e, --edit force edit of commit
--cleanup <default> how to strip spaces and #comments from message
--status include status in commit message template
-S, --gpg-sign[=<key-id>]
GPG sign commit
Commit contents options
-a, --all commit all changed files
-i, --include add specified files to index for commit
--interactive interactively add files
-p, --patch interactively add changes
-o, --only commit only specified files
-n, --no-verify bypass pre-commit and commit-msg hooks
--dry-run show what would be committed
--short show status concisely
--branch show branch information
--ahead-behind compute full ahead/behind values
--porcelain machine-readable output
--long show status in long format (default)
-z, --null terminate entries with NUL
--amend amend previous commit
--no-post-rewrite bypass post-rewrite hook
-u, --untracked-files[=<mode>]
show untracked files, optional modes: all, normal, no. (Default: all)结束。