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diff --git a/Documentation/gitcli.txt b/Documentation/gitcli.txt new file mode 100644 index 0000000000..9f13266a68 --- /dev/null +++ b/Documentation/gitcli.txt @@ -0,0 +1,214 @@ +gitcli(7) +========= + +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 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. ++ +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 `*.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 +--------------------------------------------- + +--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 http://marc.info/?l=git&m=116563135620359 and +http://marc.info/?l=git&m=119150393620273 for further +information. + +GIT +--- +Part of the linkgit:git[1] suite |