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 their arguments. Here are the rules:
Revisions come first and then paths. E.g. in
git diff v1.0 v2.0 arch/x86 include/asm-x86,
v2.0are revisions and
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 -- HEADis, "I have a file called HEAD in my work tree. Please show changes between the version I staged in the index and what I have in the work tree for that file", not "show difference between the HEAD commit and the work tree as a whole". You can say
git diff HEAD --to ask for the latter.
--, Git makes a reasonable guess, but errors out and asking you to disambiguate when ambiguous. E.g. if you have a file called HEAD in your work tree,
git diff HEADis ambiguous, and you have to say either
git diff HEAD --or
git diff -- HEADto disambiguate.
When writing a script that is expected to handle random user-input, it is a good practice to make it explicit which arguments are which by placing disambiguating
--at appropriate places.
Many commands allow wildcards in paths, but you need to protect them from getting globbed by the shell. These two mean different things:
$ git checkout -- *.c $ git checkout -- \*.c
The former lets your shell expand the fileglob, and you are asking the dot-C files in your working tree to be overwritten with the version in the index. The latter passes the
*.cto Git, and you are asking the paths in the index that match the pattern to be checked out to your working tree. After running
git add hello.c; rm hello.c, you will not see
hello.cin your working tree with the former, but with the latter you will.
Just as the filesystem . (period) refers to the current directory, using a . as a repository name in Git (a dot-repository) is a relative path and means your current repository.
Here are the rules regarding the "flags" that you should follow when you are scripting Git:
it’s preferred to use the non-dashed form of Git commands, which means that you should prefer
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. In other words, write
git foo -oArginstead of
git foo -o Argfor short options, and
git foo --long-opt=Arginstead of
git foo --long-opt Argfor long options. An option that takes optional option-argument must be written in the stuck form.
when you give a revision parameter to a command, make sure the parameter is not ambiguous with a name of a file in the work tree. E.g. do not write
git log -1 HEADbut write
git log -1 HEAD --; the former will not work if you happen to have a file called
HEADin the work tree.
many commands allow a long option
--optionto be abbreviated only to their unique prefix (e.g. if there is no other option whose name begins with
opt, you may be able to spell
--optto invoke the
--optionflag), but you should fully spell them out when writing your scripts; later versions of Git may introduce a new 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 the time of the writing though) come with an enhanced option parser.
Here is a list of the facilities provided by this option parser.
Commands which have the enhanced option parser activated all understand a couple of magic command-line options:
gives a pretty printed usage of the command.
$ git describe -h usage: git describe [options] <commit-ish>* or: git describe [options] --dirty --contains find the tag that comes after the commit --debug debug search strategy on stderr --all use any ref --tags use any tag, even unannotated --long always use long format --abbrev[=<n>] use <n> digits to display SHA-1s
Some Git commands take options that are only used for plumbing or that are deprecated, and such options are hidden from the default usage. This option gives the full list of options.
Options with long option names can be negated by prefixing
git branch has the option
--track which is on by default. You
--no-track to override that behaviour. The same goes for
Aggregating short options
Commands that support the enhanced option parser allow you to aggregate short
options. This means that you can for example use
git rm -rf or
git clean -fdx.
Abbreviating long options
Commands that support the enhanced option parser accepts unique
prefix of a long option as if it is fully spelled out, but use this
with a caution. For example,
git commit --amen behaves as if you
git commit --amend, but that is true only until a later version
of Git introduces another option that shares the same prefix,
git commit --amenity option.
Separating argument from the option
You can write the mandatory option parameter to an option as a separate word on the command line. That means that all the following uses work:
$ git foo --long-opt=Arg $ git foo --long-opt Arg $ git foo -oArg $ git foo -o Arg
However, this is NOT allowed for switches with an optional value, where the stuck form must be used:
$ git describe --abbrev HEAD # correct $ git describe --abbrev=10 HEAD # correct $ git describe --abbrev 10 HEAD # NOT WHAT YOU MEANT
NOTES ON FREQUENTLY CONFUSED OPTIONS
Many commands that can work on files in the working tree
and/or in the index can take
options. Sometimes people incorrectly think that, because
the index was originally called cache, these two are
synonyms. They are not — these two options mean very
--cachedoption is used to ask a command that usually works on files in the working tree to only work with the index. For example,
git grep, when used without a commit to specify from which commit to look for strings in, usually works on files in the working tree, but with the
--cachedoption, it looks for strings in the index.
--indexoption is used to ask a command that usually works on files in the working tree to also affect the index. For example,
git stash applyusually merges changes recorded in a stash to the working tree, but with the
--indexoption, it also merges changes to the index as well.
git apply command can be used with
--index (but not at the same time). Usually the command
only affects the files in the working tree, but with
--index, it patches both the files and their index
entries, and with
--cached, it modifies only the index
Part of the git(1) suite