интерфейс командной строки Git и соглашения (Git command-line interface and conventions)
Имя (Name)
gitcli - Git command-line interface and conventions
Синопсис (Synopsis)
gitcli
Описание (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
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, v1.0 and v2.0 are revisions
and arch/x86 and include/asm-x86 are 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
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.
• Without disambiguating --, 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 HEAD is ambiguous, and you have to say either git diff
HEAD -- or git diff -- HEAD to disambiguate.
• Because -- disambiguates revisions and paths in some
commands, it cannot be used for those commands to separate
options and revisions. You can use --end-of-options for this
(it also works for commands that do not distinguish between
revisions in paths, in which case it is simply an alias for
--).
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 restore *.c
$ git restore \*.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 *.c to
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.c in 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 git foo to git-foo.
• splitting short options to separate words (prefer git foo -a
-b to 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 -oArg instead of git foo
-o Arg for short options, and git foo --long-opt=Arg instead
of git foo --long-opt Arg for 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 HEAD but write git
log -1 HEAD --; the former will not work if you happen to
have a file called HEAD in the work tree.
• many commands allow a long option --option to 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 --opt to
invoke the --option flag), 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.
Magic Options
Commands which have the enhanced option parser activated all
understand a couple of magic command-line options:
-h
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
Note that some subcommand (e.g. git grep) may behave
differently when there are things on the command line other
than -h, but git subcmd -h without anything else on the
command line is meant to consistently give the usage.
--help-all
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.
Negating options
Options with long option names can be negated by prefixing --no-.
For example, git branch has the option --track which is on by
default. You can use --no-track to override that behaviour. The
same goes for --color and --no-color.
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 typed git commit --amend, but that is true only until a later
version of 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
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 --cached and/or --index 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 different things.
• The --cached option 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 --cached
option, it looks for strings in the index.
• The --index option is used to ask a command that usually
works on files in the working tree to also affect the index.
For example, git stash apply usually merges changes recorded
in a stash entry to the working tree, but with the --index
option, it also merges changes to the index as well.
git apply command can be used with --cached and --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 entries.
See also
https://lore.kernel.org/git/7v64clg5u9.fsf@assigned-by-dhcp.cox.net/
and
https://lore.kernel.org/git/7vy7ej9g38.fsf@gitster.siamese.dyndns.org/
for further information.
Some other commands that also work on files in the working tree
and/or in the index can take --staged and/or --worktree.
• --staged is exactly like --cached, which is used to ask a
command to only work on the index, not the working tree.
• --worktree is the opposite, to ask a command to work on the
working tree only, not the index.
• The two options can be specified together to ask a command to
work on both the index and the working tree.
