一般我們都是通過.gitignore檔案來現實commit時不提交一編譯中間檔案。但.gitignore有個缺點，即當之前該檔案已經被跟蹤（track），那麼再把這個檔名新增到.gitignore中就沒有用了。

不過網上有很多文章說，通過以下命令讓.gitignore生效：

git rm -rf --cache xxx.h

但執行完該命令，再commit的時候發現remote上的該檔案被刪除了。如果我們需要繼續保留該檔案，只是不提交當前的change，該怎麼辦了？比如應用的一些配置檔案，初始化的配置檔案需要當然要在remote上存在的，但不希望我們個人的配置資訊push到remote上。

此時，就需要以下命令來實現了（暫時取消config.ini跟蹤）：

認為未改變

git update-index --assume-unchanged config.ini

取消認為未改變

git update-index --no-assume-unchanged config.ini

附：

$ git update-index -help
usage: git update-index [<options>] [--] [<file>...]

    -q                    continue refresh even when
 
 index needs update
    --ignore-submodules   refresh: ignore submodules
    --add                 do not ignore new files
    --replace             let files replace directories and vice-versa
    --remove              notice files missing from worktree
    --unmerged            refresh even if index contains unmerged entries
 
    --refresh             refresh stat information
    --really-refresh      like --refresh, but ignore assume-unchanged setting
    --cacheinfo <mode>,<object>,<path>
                          add the specified entry to the index
    --chmod (+/-)x        override the executable bit of the listed files
    --assume-unchanged    mark files as "not changing"
    --no-assume-unchanged
                          clear assumed-unchanged bit
    --skip-worktree       mark files as "index-only"
    --no-skip-worktree    clear skip-worktree bit
    --info-only           add to index only; do not add content to object database
    --force-remove        remove named paths even if present in worktree
    -z                    with --stdin: input lines are terminated by null bytes
    --stdin               read list of paths to be updated from standard input
    --index-info          add entries from standard input to the index
    --unresolve           repopulate stages #2 and #3 for the listed paths
    -g, --again           only update entries that differ from HEAD
    --ignore-missing      ignore files missing from worktree
    --verbose             report actions to standard output
    --clear-resolve-undo  (for porcelains) forget saved unresolved conflicts
    --index-version <n>   write index in this format
    --split-index         enable or disable split index
    --untracked-cache     enable/disable untracked cache
    --test-untracked-cache
                          test if the filesystem supports untracked cache
    --force-untracked-cache
                          enable untracked cache without testing the filesystem