NAME

gitcli - Git command-line interface and conventions

SYNOPSIS

gitcli

DESCRIPTION

This manual describes the convention used throughout Git CLI.

Many commands take revisions (most often "commits", but sometimes"tree-ish", depending on the context and command) and paths as theirarguments. Here are the rules:

  • Revisions come first and then paths.E.g. in git diff v1.0 v2.0 arch/x86 include/asm-x86,v1.0 and v2.0 are revisions and arch/x86 and include/asm-x86are paths.

  • When an argument can be misunderstood as either a revision or a path,they can be disambiguated by placing — between them.E.g. git diff — HEAD is, "I have a file called HEAD in my worktree. Please show changes between the version I staged in the indexand what I have in the work tree for that file", not "show differencebetween the HEAD commit and the work tree as a whole". You can saygit diff HEAD — to ask for the latter.

  • Without disambiguating —, Git makes a reasonable guess, but errorsout and asking you to disambiguate when ambiguous. E.g. if you have afile called HEAD in your work tree, git diff HEAD is ambiguous, andyou have to say either git diff HEAD — or git diff — HEAD todisambiguate.

When writing a script that is expected to handle random user-input, it isa good practice to make it explicit which arguments are which by placingdisambiguating — at appropriate places.

  • Many commands allow wildcards in paths, but you need to protectthem from getting globbed by the shell. These two mean differentthings:
  1. $ git restore *.c
  2. $ git restore \*.c

The former lets your shell expand the fileglob, and you are askingthe dot-C files in your working tree to be overwritten with the versionin the index. The latter passes the *.c to Git, and you are askingthe paths in the index that match the pattern to be checked out to yourworking tree. After running git add hello.c; rm hello.c, you will _not_see hello.c in your working tree with the former, but with the latteryou will.

  • Just as the filesystem . (period) refers to the current directory,using a . as a repository name in Git (a dot-repository) is a relativepath and means your current repository.

Here are the rules regarding the "flags" that you should follow when you arescripting Git:

  • it’s preferred to use the non-dashed form of Git commands, which means thatyou should prefer git foo to git-foo.

  • splitting short options to separate words (prefer git foo -a -bto git foo -ab, the latter may not even work).

  • when a command-line option takes an argument, use the stuck form. Inother words, write git foo -oArg instead of git foo -o Arg for shortoptions, and git foo —long-opt=Arg instead of git foo —long-opt Argfor long options. An option that takes optional option-argument must bewritten in the stuck form.

  • when you give a revision parameter to a command, make sure the parameter isnot ambiguous with a name of a file in the work tree. E.g. do not writegit log -1 HEAD but write git log -1 HEAD —; the former will not workif you happen to have a file called HEAD in the work tree.

  • many commands allow a long option —option to be abbreviatedonly to their unique prefix (e.g. if there is no other optionwhose name begins with opt, you may be able to spell —opt toinvoke the —option flag), but you should fully spell them outwhen writing your scripts; later versions of Git may introduce anew option whose name shares the same prefix, e.g. —optimize,to make a short prefix that used to be unique no longer unique.

ENHANCED OPTION PARSER

From the Git 1.5.4 series and further, many Git commands (not all of them at thetime of the writing though) come with an enhanced option parser.

Here is a list of the facilities provided by this option parser.

Magic Options

Commands which have the enhanced option parser activated all understand acouple of magic command-line options:

  • -h
  • gives a pretty printed usage of the command.
  1. $ git describe -h
  2. usage: git describe [<options>] <commit-ish>*
  3.    or: git describe [<options>] --dirty
  4.  
  5.     --contains            find the tag that comes after the commit
  6.     --debug               debug search strategy on stderr
  7.     --all                 use any ref
  8.     --tags                use any tag, even unannotated
  9.     --long                always use long format
  10.     --abbrev[=<n>]        use <n> digits to display SHA-1s
  • —help-all
  • Some Git commands take options that are only used for plumbing or thatare deprecated, and such options are hidden from the default usage. Thisoption gives the full list of options.

Negating options

Options with long option names can be negated by prefixing —no-. Forexample, git branch has the option —track which is on by default. Youcan use —no-track to override that behaviour. The same goes for —colorand —no-color.

Aggregating short options

Commands that support the enhanced option parser allow you to aggregate shortoptions. This means that you can for example use git rm -rf orgit clean -fdx.

Abbreviating long options

Commands that support the enhanced option parser accepts uniqueprefix of a long option as if it is fully spelled out, but use thiswith a caution. For example, git commit —amen behaves as if youtyped git commit —amend, but that is true only until a later versionof Git introduces another option that shares the same prefix,e.g. git commit —amenity option.

Separating argument from the option

You can write the mandatory option parameter to an option as a separateword on the command line. That means that all the following uses work:

  1. $ git foo --long-opt=Arg
  2. $ git foo --long-opt Arg
  3. $ git foo -oArg
  4. $ git foo -o Arg

However, this is NOT allowed for switches with an optional value, where thestuck form must be used:

  1. $ git describe --abbrev HEAD     # correct
  2. $ git describe --abbrev=10 HEAD  # correct
  3. $ git describe --abbrev 10 HEAD  # NOT WHAT YOU MEANT

NOTES ON FREQUENTLY CONFUSED OPTIONS

Many commands that can work on files in the working treeand/or in the index can take —cached and/or —indexoptions. Sometimes people incorrectly think that, becausethe index was originally called cache, these two aresynonyms. They are not — these two options mean verydifferent things.

  • The —cached option is used to ask a command thatusually works on files in the working tree to only workwith the index. For example, git grep, when usedwithout a commit to specify from which commit to look forstrings in, usually works on files in the working tree,but with the —cached option, it looks for strings inthe index.

  • The —index option is used to ask a command thatusually works on files in the working tree to alsoaffect the index. For example, git stash apply usuallymerges changes recorded in a stash entry to the working tree,but with the —index option, it also merges changes tothe index as well.

git apply command can be used with —cached and—index (but not at the same time). Usually the commandonly affects the files in the working tree, but with—index, it patches both the files and their indexentries, and with —cached, it modifies only the indexentries.

See also http://marc.info/?l=git&m=116563135620359 andhttp://marc.info/?l=git&m=119150393620273 for furtherinformation.

Some other commands that also work on files in the working tree and/orin the index can take —staged and/or —worktree.

  • —staged is exactly like —cached, which is used to ask acommand to only work on the index, not the working tree.

  • —worktree is the opposite, to ask a command to work on theworking tree only, not the index.

  • The two options can be specified together to ask a command to workon both the index and the working tree.

GIT

Part of the git[1] suite