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https://git-scm.com/
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Document expected behavior in the case of errors #856

Closed andrewzhaosc closed 7 years ago

andrewzhaosc commented 8 years ago

for example, network errors, permissions errors, etc.

what are the outputs, return codes, side effects?

sxlijin commented 7 years ago

This is all well documented in the man pages. If you have issues with any of the actual documentation, please reach out to the community.

andrewzhaosc commented 7 years ago

where is it then?

I tried searching for return codes but I'm here because I couldn't find it in the man page

Here's the man page. Why don't you point it out to me.

GIT(1)                            Git Manual                            GIT(1)

NAME
       git - the stupid content tracker

SYNOPSIS
       git [--version] [--help] [-C <path>] [-c <name>=<value>]
           [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]
           [-p|--paginate|--no-pager] [--no-replace-objects] [--bare]
           [--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]
           <command> [<args>]

DESCRIPTION
       Git is a fast, scalable, distributed revision control system with an
       unusually rich command set that provides both high-level operations and
       full access to internals.

       See gittutorial(7) to get started, then see giteveryday(7) for a useful
       minimum set of commands. The Git User's Manual[1] has a more in-depth
       introduction.

       After you mastered the basic concepts, you can come back to this page
       to learn what commands Git offers. You can learn more about individual
       Git commands with "git help command". gitcli(7) manual page gives you
       an overview of the command-line command syntax.

       Formatted and hyperlinked version of the latest Git documentation can
       be viewed at http://git-htmldocs.googlecode.com/git/git.html.

OPTIONS
       --version
           Prints the Git suite version that the git program came from.

       --help
           Prints the synopsis and a list of the most commonly used commands.
           If the option --all or -a is given then all available commands are
           printed. If a Git command is named this option will bring up the
           manual page for that command.

           Other options are available to control how the manual page is
           displayed. See git-help(1) for more information, because git --help
           ...  is converted internally into git help ....

       -C <path>
           Run as if git was started in <path> instead of the current working
           directory. When multiple -C options are given, each subsequent
           non-absolute -C <path> is interpreted relative to the preceding -C
           <path>.

           This option affects options that expect path name like --git-dir
           and --work-tree in that their interpretations of the path names
           would be made relative to the working directory caused by the -C
           option. For example the following invocations are equivalent:

               git --git-dir=a.git --work-tree=b -C c status
               git --git-dir=c/a.git --work-tree=c/b status

       -c <name>=<value>
           Pass a configuration parameter to the command. The value given will
           override values from configuration files. The <name> is expected in
           the same format as listed by git config (subkeys separated by
           dots).

           Note that omitting the = in git -c foo.bar ...  is allowed and sets
           foo.bar to the boolean true value (just like [foo]bar would in a
           config file). Including the equals but with an empty value (like
           git -c foo.bar= ...) sets foo.bar to the empty string.

       --exec-path[=<path>]
           Path to wherever your core Git programs are installed. This can
           also be controlled by setting the GIT_EXEC_PATH environment
           variable. If no path is given, git will print the current setting
           and then exit.

       --html-path
           Print the path, without trailing slash, where Git's HTML
           documentation is installed and exit.

       --man-path
           Print the manpath (see man(1)) for the man pages for this version
           of Git and exit.

       --info-path
           Print the path where the Info files documenting this version of Git
           are installed and exit.

       -p, --paginate
           Pipe all output into less (or if set, $PAGER) if standard output is
           a terminal. This overrides the pager.<cmd> configuration options
           (see the "Configuration Mechanism" section below).

       --no-pager
           Do not pipe Git output into a pager.

       --git-dir=<path>
           Set the path to the repository. This can also be controlled by
           setting the GIT_DIR environment variable. It can be an absolute
           path or relative path to current working directory.

       --work-tree=<path>
           Set the path to the working tree. It can be an absolute path or a
           path relative to the current working directory. This can also be
           controlled by setting the GIT_WORK_TREE environment variable and
           the core.worktree configuration variable (see core.worktree in git-
           config(1) for a more detailed discussion).

       --namespace=<path>
           Set the Git namespace. See gitnamespaces(7) for more details.
           Equivalent to setting the GIT_NAMESPACE environment variable.

       --bare
           Treat the repository as a bare repository. If GIT_DIR environment
           is not set, it is set to the current working directory.

       --no-replace-objects
           Do not use replacement refs to replace Git objects. See git-
           replace(1) for more information.

       --literal-pathspecs
           Treat pathspecs literally (i.e. no globbing, no pathspec magic).
           This is equivalent to setting the GIT_LITERAL_PATHSPECS environment
           variable to 1.

       --glob-pathspecs
           Add "glob" magic to all pathspec. This is equivalent to setting the
           GIT_GLOB_PATHSPECS environment variable to 1. Disabling globbing on
           individual pathspecs can be done using pathspec magic ":(literal)"

       --noglob-pathspecs
           Add "literal" magic to all pathspec. This is equivalent to setting
           the GIT_NOGLOB_PATHSPECS environment variable to 1. Enabling
           globbing on individual pathspecs can be done using pathspec magic
           ":(glob)"

       --icase-pathspecs
           Add "icase" magic to all pathspec. This is equivalent to setting
           the GIT_ICASE_PATHSPECS environment variable to 1.

GIT COMMANDS
       We divide Git into high level ("porcelain") commands and low level
       ("plumbing") commands.

HIGH-LEVEL COMMANDS (PORCELAIN)
       We separate the porcelain commands into the main commands and some
       ancillary user utilities.

   Main porcelain commands
       git-add(1)
           Add file contents to the index.

       git-am(1)
           Apply a series of patches from a mailbox.

       git-archive(1)
           Create an archive of files from a named tree.

       git-bisect(1)
           Use binary search to find the commit that introduced a bug.

       git-branch(1)
           List, create, or delete branches.

       git-bundle(1)
           Move objects and refs by archive.

       git-checkout(1)
           Switch branches or restore working tree files.

       git-cherry-pick(1)
           Apply the changes introduced by some existing commits.

       git-citool(1)
           Graphical alternative to git-commit.

       git-clean(1)
           Remove untracked files from the working tree.

       git-clone(1)
           Clone a repository into a new directory.

       git-commit(1)
           Record changes to the repository.

       git-describe(1)
           Describe a commit using the most recent tag reachable from it.

       git-diff(1)
           Show changes between commits, commit and working tree, etc.

       git-fetch(1)
           Download objects and refs from another repository.

       git-format-patch(1)
           Prepare patches for e-mail submission.

       git-gc(1)
           Cleanup unnecessary files and optimize the local repository.

       git-grep(1)
           Print lines matching a pattern.

       git-gui(1)
           A portable graphical interface to Git.

       git-init(1)
           Create an empty Git repository or reinitialize an existing one.

       git-log(1)
           Show commit logs.

       git-merge(1)
           Join two or more development histories together.

       git-mv(1)
           Move or rename a file, a directory, or a symlink.

       git-notes(1)
           Add or inspect object notes.

       git-pull(1)
           Fetch from and integrate with another repository or a local branch.

       git-push(1)
           Update remote refs along with associated objects.

       git-rebase(1)
           Forward-port local commits to the updated upstream head.

       git-reset(1)
           Reset current HEAD to the specified state.

       git-revert(1)
           Revert some existing commits.

       git-rm(1)
           Remove files from the working tree and from the index.

       git-shortlog(1)
           Summarize git log output.

       git-show(1)
           Show various types of objects.

       git-stash(1)
           Stash the changes in a dirty working directory away.

       git-status(1)
           Show the working tree status.

       git-submodule(1)
           Initialize, update or inspect submodules.

       git-tag(1)
           Create, list, delete or verify a tag object signed with GPG.

       git-worktree(1)
           Manage multiple working trees.

       gitk(1)
           The Git repository browser.

   Ancillary Commands
       Manipulators:

       git-config(1)
           Get and set repository or global options.

       git-fast-export(1)
           Git data exporter.

       git-fast-import(1)
           Backend for fast Git data importers.

       git-filter-branch(1)
           Rewrite branches.

       git-mergetool(1)
           Run merge conflict resolution tools to resolve merge conflicts.

       git-pack-refs(1)
           Pack heads and tags for efficient repository access.

       git-prune(1)
           Prune all unreachable objects from the object database.

       git-reflog(1)
           Manage reflog information.

       git-relink(1)
           Hardlink common objects in local repositories.

       git-remote(1)
           Manage set of tracked repositories.

       git-repack(1)
           Pack unpacked objects in a repository.

       git-replace(1)
           Create, list, delete refs to replace objects.

       Interrogators:

       git-annotate(1)
           Annotate file lines with commit information.

       git-blame(1)
           Show what revision and author last modified each line of a file.

       git-cherry(1)
           Find commits yet to be applied to upstream.

       git-count-objects(1)
           Count unpacked number of objects and their disk consumption.

       git-difftool(1)
           Show changes using common diff tools.

       git-fsck(1)
           Verifies the connectivity and validity of the objects in the
           database.

       git-get-tar-commit-id(1)
           Extract commit ID from an archive created using git-archive.

       git-help(1)
           Display help information about Git.

       git-instaweb(1)
           Instantly browse your working repository in gitweb.

       git-merge-tree(1)
           Show three-way merge without touching index.

       git-rerere(1)
           Reuse recorded resolution of conflicted merges.

       git-rev-parse(1)
           Pick out and massage parameters.

       git-show-branch(1)
           Show branches and their commits.

       git-verify-commit(1)
           Check the GPG signature of commits.

       git-verify-tag(1)
           Check the GPG signature of tags.

       git-whatchanged(1)
           Show logs with difference each commit introduces.

       gitweb(1)
           Git web interface (web frontend to Git repositories).

   Interacting with Others
       These commands are to interact with foreign SCM and with other people
       via patch over e-mail.

       git-archimport(1)
           Import an Arch repository into Git.

       git-cvsexportcommit(1)
           Export a single commit to a CVS checkout.

       git-cvsimport(1)
           Salvage your data out of another SCM people love to hate.

       git-cvsserver(1)
           A CVS server emulator for Git.

       git-imap-send(1)
           Send a collection of patches from stdin to an IMAP folder.

       git-p4(1)
           Import from and submit to Perforce repositories.

       git-quiltimport(1)
           Applies a quilt patchset onto the current branch.

       git-request-pull(1)
           Generates a summary of pending changes.

       git-send-email(1)
           Send a collection of patches as emails.

       git-svn(1)
           Bidirectional operation between a Subversion repository and Git.

LOW-LEVEL COMMANDS (PLUMBING)
       Although Git includes its own porcelain layer, its low-level commands
       are sufficient to support development of alternative porcelains.
       Developers of such porcelains might start by reading about git-update-
       index(1) and git-read-tree(1).

       The interface (input, output, set of options and the semantics) to
       these low-level commands are meant to be a lot more stable than
       Porcelain level commands, because these commands are primarily for
       scripted use. The interface to Porcelain commands on the other hand are
       subject to change in order to improve the end user experience.

       The following description divides the low-level commands into commands
       that manipulate objects (in the repository, index, and working tree),
       commands that interrogate and compare objects, and commands that move
       objects and references between repositories.

   Manipulation commands
       git-apply(1)
           Apply a patch to files and/or to the index.

       git-checkout-index(1)
           Copy files from the index to the working tree.

       git-commit-tree(1)
           Create a new commit object.

       git-hash-object(1)
           Compute object ID and optionally creates a blob from a file.

       git-index-pack(1)
           Build pack index file for an existing packed archive.

       git-merge-file(1)
           Run a three-way file merge.

       git-merge-index(1)
           Run a merge for files needing merging.

       git-mktag(1)
           Creates a tag object.

       git-mktree(1)
           Build a tree-object from ls-tree formatted text.

       git-pack-objects(1)
           Create a packed archive of objects.

       git-prune-packed(1)
           Remove extra objects that are already in pack files.

       git-read-tree(1)
           Reads tree information into the index.

       git-symbolic-ref(1)
           Read, modify and delete symbolic refs.

       git-unpack-objects(1)
           Unpack objects from a packed archive.

       git-update-index(1)
           Register file contents in the working tree to the index.

       git-update-ref(1)
           Update the object name stored in a ref safely.

       git-write-tree(1)
           Create a tree object from the current index.

   Interrogation commands
       git-cat-file(1)
           Provide content or type and size information for repository
           objects.

       git-diff-files(1)
           Compares files in the working tree and the index.

       git-diff-index(1)
           Compare a tree to the working tree or index.

       git-diff-tree(1)
           Compares the content and mode of blobs found via two tree objects.

       git-for-each-ref(1)
           Output information on each ref.

       git-ls-files(1)
           Show information about files in the index and the working tree.

       git-ls-remote(1)
           List references in a remote repository.

       git-ls-tree(1)
           List the contents of a tree object.

       git-merge-base(1)
           Find as good common ancestors as possible for a merge.

       git-name-rev(1)
           Find symbolic names for given revs.

       git-pack-redundant(1)
           Find redundant pack files.

       git-rev-list(1)
           Lists commit objects in reverse chronological order.

       git-show-index(1)
           Show packed archive index.

       git-show-ref(1)
           List references in a local repository.

       git-unpack-file(1)
           Creates a temporary file with a blob's contents.

       git-var(1)
           Show a Git logical variable.

       git-verify-pack(1)
           Validate packed Git archive files.

       In general, the interrogate commands do not touch the files in the
       working tree.

   Synching repositories
       git-daemon(1)
           A really simple server for Git repositories.

       git-fetch-pack(1)
           Receive missing objects from another repository.

       git-http-backend(1)
           Server side implementation of Git over HTTP.

       git-send-pack(1)
           Push objects over Git protocol to another repository.

       git-update-server-info(1)
           Update auxiliary info file to help dumb servers.

       The following are helper commands used by the above; end users
       typically do not use them directly.

       git-http-fetch(1)
           Download from a remote Git repository via HTTP.

       git-http-push(1)
           Push objects over HTTP/DAV to another repository.

       git-parse-remote(1)
           Routines to help parsing remote repository access parameters.

       git-receive-pack(1)
           Receive what is pushed into the repository.

       git-shell(1)
           Restricted login shell for Git-only SSH access.

       git-upload-archive(1)
           Send archive back to git-archive.

       git-upload-pack(1)
           Send objects packed back to git-fetch-pack.

   Internal helper commands
       These are internal helper commands used by other commands; end users
       typically do not use them directly.

       git-check-attr(1)
           Display gitattributes information.

       git-check-ignore(1)
           Debug gitignore / exclude files.

       git-check-mailmap(1)
           Show canonical names and email addresses of contacts.

       git-check-ref-format(1)
           Ensures that a reference name is well formed.

       git-column(1)
           Display data in columns.

       git-credential(1)
           Retrieve and store user credentials.

       git-credential-cache(1)
           Helper to temporarily store passwords in memory.

       git-credential-store(1)
           Helper to store credentials on disk.

       git-fmt-merge-msg(1)
           Produce a merge commit message.

       git-interpret-trailers(1)
           help add structured information into commit messages.

       git-mailinfo(1)
           Extracts patch and authorship from a single e-mail message.

       git-mailsplit(1)
           Simple UNIX mbox splitter program.

       git-merge-one-file(1)
           The standard helper program to use with git-merge-index.

       git-patch-id(1)
           Compute unique ID for a patch.

       git-sh-i18n(1)
           Git's i18n setup code for shell scripts.

       git-sh-setup(1)
           Common Git shell script setup code.

       git-stripspace(1)
           Remove unnecessary whitespace.

CONFIGURATION MECHANISM
       Git uses a simple text format to store customizations that are per
       repository and are per user. Such a configuration file may look like
       this:

           #
           # A '#' or ';' character indicates a comment.
           #

           ; core variables
           [core]
                   ; Don't trust file modes
                   filemode = false

           ; user identity
           [user]
                   name = "Junio C Hamano"
                   email = "gitster@pobox.com"

       Various commands read from the configuration file and adjust their
       operation accordingly. See git-config(1) for a list and more details
       about the configuration mechanism.

IDENTIFIER TERMINOLOGY
       <object>
           Indicates the object name for any type of object.

       <blob>
           Indicates a blob object name.

       <tree>
           Indicates a tree object name.

       <commit>
           Indicates a commit object name.

       <tree-ish>
           Indicates a tree, commit or tag object name. A command that takes a
           <tree-ish> argument ultimately wants to operate on a <tree> object
           but automatically dereferences <commit> and <tag> objects that
           point at a <tree>.

       <commit-ish>
           Indicates a commit or tag object name. A command that takes a
           <commit-ish> argument ultimately wants to operate on a <commit>
           object but automatically dereferences <tag> objects that point at a
           <commit>.

       <type>
           Indicates that an object type is required. Currently one of: blob,
           tree, commit, or tag.

       <file>
           Indicates a filename - almost always relative to the root of the
           tree structure GIT_INDEX_FILE describes.

SYMBOLIC IDENTIFIERS
       Any Git command accepting any <object> can also use the following
       symbolic notation:

       HEAD
           indicates the head of the current branch.

       <tag>
           a valid tag name (i.e. a refs/tags/<tag> reference).

       <head>
           a valid head name (i.e. a refs/heads/<head> reference).

       For a more complete list of ways to spell object names, see "SPECIFYING
       REVISIONS" section in gitrevisions(7).

FILE/DIRECTORY STRUCTURE
       Please see the gitrepository-layout(5) document.

       Read githooks(5) for more details about each hook.

       Higher level SCMs may provide and manage additional information in the
       $GIT_DIR.

TERMINOLOGY
       Please see gitglossary(7).

ENVIRONMENT VARIABLES
       Various Git commands use the following environment variables:

   The Git Repository
       These environment variables apply to all core Git commands. Nb: it is
       worth noting that they may be used/overridden by SCMS sitting above Git
       so take care if using a foreign front-end.

       GIT_INDEX_FILE
           This environment allows the specification of an alternate index
           file. If not specified, the default of $GIT_DIR/index is used.

       GIT_INDEX_VERSION
           This environment variable allows the specification of an index
           version for new repositories. It won't affect existing index files.
           By default index file version 2 or 3 is used. See git-update-
           index(1) for more information.

       GIT_OBJECT_DIRECTORY
           If the object storage directory is specified via this environment
           variable then the sha1 directories are created underneath -
           otherwise the default $GIT_DIR/objects directory is used.

       GIT_ALTERNATE_OBJECT_DIRECTORIES
           Due to the immutable nature of Git objects, old objects can be
           archived into shared, read-only directories. This variable
           specifies a ":" separated (on Windows ";" separated) list of Git
           object directories which can be used to search for Git objects. New
           objects will not be written to these directories.

       GIT_DIR
           If the GIT_DIR environment variable is set then it specifies a path
           to use instead of the default .git for the base of the repository.
           The --git-dir command-line option also sets this value.

       GIT_WORK_TREE
           Set the path to the root of the working tree. This can also be
           controlled by the --work-tree command-line option and the
           core.worktree configuration variable.

       GIT_NAMESPACE
           Set the Git namespace; see gitnamespaces(7) for details. The
           --namespace command-line option also sets this value.

       GIT_CEILING_DIRECTORIES
           This should be a colon-separated list of absolute paths. If set, it
           is a list of directories that Git should not chdir up into while
           looking for a repository directory (useful for excluding
           slow-loading network directories). It will not exclude the current
           working directory or a GIT_DIR set on the command line or in the
           environment. Normally, Git has to read the entries in this list and
           resolve any symlink that might be present in order to compare them
           with the current directory. However, if even this access is slow,
           you can add an empty entry to the list to tell Git that the
           subsequent entries are not symlinks and needn't be resolved; e.g.,
           GIT_CEILING_DIRECTORIES=/maybe/symlink::/very/slow/non/symlink.

       GIT_DISCOVERY_ACROSS_FILESYSTEM
           When run in a directory that does not have ".git" repository
           directory, Git tries to find such a directory in the parent
           directories to find the top of the working tree, but by default it
           does not cross filesystem boundaries. This environment variable can
           be set to true to tell Git not to stop at filesystem boundaries.
           Like GIT_CEILING_DIRECTORIES, this will not affect an explicit
           repository directory set via GIT_DIR or on the command line.

       GIT_COMMON_DIR
           If this variable is set to a path, non-worktree files that are
           normally in $GIT_DIR will be taken from this path instead.
           Worktree-specific files such as HEAD or index are taken from
           $GIT_DIR. See gitrepository-layout(5) and git-worktree(1) for
           details. This variable has lower precedence than other path
           variables such as GIT_INDEX_FILE, GIT_OBJECT_DIRECTORY...

   Git Commits
       GIT_AUTHOR_NAME, GIT_AUTHOR_EMAIL, GIT_AUTHOR_DATE, GIT_COMMITTER_NAME,
       GIT_COMMITTER_EMAIL, GIT_COMMITTER_DATE, EMAIL
           see git-commit-tree(1)

   Git Diffs
       GIT_DIFF_OPTS
           Only valid setting is "--unified=??" or "-u??" to set the number of
           context lines shown when a unified diff is created. This takes
           precedence over any "-U" or "--unified" option value passed on the
           Git diff command line.

       GIT_EXTERNAL_DIFF
           When the environment variable GIT_EXTERNAL_DIFF is set, the program
           named by it is called, instead of the diff invocation described
           above. For a path that is added, removed, or modified,
           GIT_EXTERNAL_DIFF is called with 7 parameters:

               path old-file old-hex old-mode new-file new-hex new-mode

           where:

       <old|new>-file
           are files GIT_EXTERNAL_DIFF can use to read the contents of
           <old|new>,

       <old|new>-hex
           are the 40-hexdigit SHA-1 hashes,

       <old|new>-mode
           are the octal representation of the file modes.

           The file parameters can point at the user's working file (e.g.
           new-file in "git-diff-files"), /dev/null (e.g.  old-file when a new
           file is added), or a temporary file (e.g.  old-file in the index).
           GIT_EXTERNAL_DIFF should not worry about unlinking the temporary
           file --- it is removed when GIT_EXTERNAL_DIFF exits.

           For a path that is unmerged, GIT_EXTERNAL_DIFF is called with 1
           parameter, <path>.

           For each path GIT_EXTERNAL_DIFF is called, two environment
           variables, GIT_DIFF_PATH_COUNTER and GIT_DIFF_PATH_TOTAL are set.

       GIT_DIFF_PATH_COUNTER
           A 1-based counter incremented by one for every path.

       GIT_DIFF_PATH_TOTAL
           The total number of paths.

   other
       GIT_MERGE_VERBOSITY
           A number controlling the amount of output shown by the recursive
           merge strategy. Overrides merge.verbosity. See git-merge(1)

       GIT_PAGER
           This environment variable overrides $PAGER. If it is set to an
           empty string or to the value "cat", Git will not launch a pager.
           See also the core.pager option in git-config(1).

       GIT_EDITOR
           This environment variable overrides $EDITOR and $VISUAL. It is used
           by several Git commands when, on interactive mode, an editor is to
           be launched. See also git-var(1) and the core.editor option in git-
           config(1).

       GIT_SSH, GIT_SSH_COMMAND
           If either of these environment variables is set then git fetch and
           git push will use the specified command instead of ssh when they
           need to connect to a remote system. The command will be given
           exactly two or four arguments: the username@host (or just host)
           from the URL and the shell command to execute on that remote
           system, optionally preceded by -p (literally) and the port from the
           URL when it specifies something other than the default SSH port.

           $GIT_SSH_COMMAND takes precedence over $GIT_SSH, and is interpreted
           by the shell, which allows additional arguments to be included.
           $GIT_SSH on the other hand must be just the path to a program
           (which can be a wrapper shell script, if additional arguments are
           needed).

           Usually it is easier to configure any desired options through your
           personal .ssh/config file. Please consult your ssh documentation
           for further details.

       GIT_ASKPASS
           If this environment variable is set, then Git commands which need
           to acquire passwords or passphrases (e.g. for HTTP or IMAP
           authentication) will call this program with a suitable prompt as
           command-line argument and read the password from its STDOUT. See
           also the core.askPass option in git-config(1).

       GIT_TERMINAL_PROMPT
           If this environment variable is set to 0, git will not prompt on
           the terminal (e.g., when asking for HTTP authentication).

       GIT_CONFIG_NOSYSTEM
           Whether to skip reading settings from the system-wide
           $(prefix)/etc/gitconfig file. This environment variable can be used
           along with $HOME and $XDG_CONFIG_HOME to create a predictable
           environment for a picky script, or you can set it temporarily to
           avoid using a buggy /etc/gitconfig file while waiting for someone
           with sufficient permissions to fix it.

       GIT_FLUSH
           If this environment variable is set to "1", then commands such as
           git blame (in incremental mode), git rev-list, git log, git
           check-attr and git check-ignore will force a flush of the output
           stream after each record have been flushed. If this variable is set
           to "0", the output of these commands will be done using completely
           buffered I/O. If this environment variable is not set, Git will
           choose buffered or record-oriented flushing based on whether stdout
           appears to be redirected to a file or not.

       GIT_TRACE
           Enables general trace messages, e.g. alias expansion, built-in
           command execution and external command execution.

           If this variable is set to "1", "2" or "true" (comparison is case
           insensitive), trace messages will be printed to stderr.

           If the variable is set to an integer value greater than 2 and lower
           than 10 (strictly) then Git will interpret this value as an open
           file descriptor and will try to write the trace messages into this
           file descriptor.

           Alternatively, if the variable is set to an absolute path (starting
           with a / character), Git will interpret this as a file path and
           will try to write the trace messages into it.

           Unsetting the variable, or setting it to empty, "0" or "false"
           (case insensitive) disables trace messages.

       GIT_TRACE_PACK_ACCESS
           Enables trace messages for all accesses to any packs. For each
           access, the pack file name and an offset in the pack is recorded.
           This may be helpful for troubleshooting some pack-related
           performance problems. See GIT_TRACE for available trace output
           options.

       GIT_TRACE_PACKET
           Enables trace messages for all packets coming in or out of a given
           program. This can help with debugging object negotiation or other
           protocol issues. Tracing is turned off at a packet starting with
           "PACK" (but see GIT_TRACE_PACKFILE below). See GIT_TRACE for
           available trace output options.

       GIT_TRACE_PACKFILE
           Enables tracing of packfiles sent or received by a given program.
           Unlike other trace output, this trace is verbatim: no headers, and
           no quoting of binary data. You almost certainly want to direct into
           a file (e.g., GIT_TRACE_PACKFILE=/tmp/my.pack) rather than
           displaying it on the terminal or mixing it with other trace output.

           Note that this is currently only implemented for the client side of
           clones and fetches.

       GIT_TRACE_PERFORMANCE
           Enables performance related trace messages, e.g. total execution
           time of each Git command. See GIT_TRACE for available trace output
           options.

       GIT_TRACE_SETUP
           Enables trace messages printing the .git, working tree and current
           working directory after Git has completed its setup phase. See
           GIT_TRACE for available trace output options.

       GIT_TRACE_SHALLOW
           Enables trace messages that can help debugging fetching / cloning
           of shallow repositories. See GIT_TRACE for available trace output
           options.

       GIT_LITERAL_PATHSPECS
           Setting this variable to 1 will cause Git to treat all pathspecs
           literally, rather than as glob patterns. For example, running
           GIT_LITERAL_PATHSPECS=1 git log -- '*.c' will search for commits
           that touch the path *.c, not any paths that the glob *.c matches.
           You might want this if you are feeding literal paths to Git (e.g.,
           paths previously given to you by git ls-tree, --raw diff output,
           etc).

       GIT_GLOB_PATHSPECS
           Setting this variable to 1 will cause Git to treat all pathspecs as
           glob patterns (aka "glob" magic).

       GIT_NOGLOB_PATHSPECS
           Setting this variable to 1 will cause Git to treat all pathspecs as
           literal (aka "literal" magic).

       GIT_ICASE_PATHSPECS
           Setting this variable to 1 will cause Git to treat all pathspecs as
           case-insensitive.

       GIT_REFLOG_ACTION
           When a ref is updated, reflog entries are created to keep track of
           the reason why the ref was updated (which is typically the name of
           the high-level command that updated the ref), in addition to the
           old and new values of the ref. A scripted Porcelain command can use
           set_reflog_action helper function in git-sh-setup to set its name
           to this variable when it is invoked as the top level command by the
           end user, to be recorded in the body of the reflog.

       GIT_REF_PARANOIA
           If set to 1, include broken or badly named refs when iterating over
           lists of refs. In a normal, non-corrupted repository, this does
           nothing. However, enabling it may help git to detect and abort some
           operations in the presence of broken refs. Git sets this variable
           automatically when performing destructive operations like git-
           prune(1). You should not need to set it yourself unless you want to
           be paranoid about making sure an operation has touched every ref
           (e.g., because you are cloning a repository to make a backup).

       GIT_ALLOW_PROTOCOL
           If set, provide a colon-separated list of protocols which are
           allowed to be used with fetch/push/clone. This is useful to
           restrict recursive submodule initialization from an untrusted
           repository. Any protocol not mentioned will be disallowed (i.e.,
           this is a whitelist, not a blacklist). If the variable is not set
           at all, all protocols are enabled. The protocol names currently
           used by git are:

           o   file: any local file-based path (including file:// URLs, or
               local paths)

           o   git: the anonymous git protocol over a direct TCP connection
               (or proxy, if configured)

           o   ssh: git over ssh (including host:path syntax, git+ssh://,
               etc).

           o   rsync: git over rsync

           o   http: git over http, both "smart http" and "dumb http". Note
               that this does not include https; if you want both, you should
               specify both as http:https.

           o   any external helpers are named by their protocol (e.g., use hg
               to allow the git-remote-hg helper)

DISCUSSION
       More detail on the following is available from the Git concepts chapter
       of the user-manual[2] and gitcore-tutorial(7).

       A Git project normally consists of a working directory with a ".git"
       subdirectory at the top level. The .git directory contains, among other
       things, a compressed object database representing the complete history
       of the project, an "index" file which links that history to the current
       contents of the working tree, and named pointers into that history such
       as tags and branch heads.

       The object database contains objects of three main types: blobs, which
       hold file data; trees, which point to blobs and other trees to build up
       directory hierarchies; and commits, which each reference a single tree
       and some number of parent commits.

       The commit, equivalent to what other systems call a "changeset" or
       "version", represents a step in the project's history, and each parent
       represents an immediately preceding step. Commits with more than one
       parent represent merges of independent lines of development.

       All objects are named by the SHA-1 hash of their contents, normally
       written as a string of 40 hex digits. Such names are globally unique.
       The entire history leading up to a commit can be vouched for by signing
       just that commit. A fourth object type, the tag, is provided for this
       purpose.

       When first created, objects are stored in individual files, but for
       efficiency may later be compressed together into "pack files".

       Named pointers called refs mark interesting points in history. A ref
       may contain the SHA-1 name of an object or the name of another ref.
       Refs with names beginning ref/head/ contain the SHA-1 name of the most
       recent commit (or "head") of a branch under development. SHA-1 names of
       tags of interest are stored under ref/tags/. A special ref named HEAD
       contains the name of the currently checked-out branch.

       The index file is initialized with a list of all paths and, for each
       path, a blob object and a set of attributes. The blob object represents
       the contents of the file as of the head of the current branch. The
       attributes (last modified time, size, etc.) are taken from the
       corresponding file in the working tree. Subsequent changes to the
       working tree can be found by comparing these attributes. The index may
       be updated with new content, and new commits may be created from the
       content stored in the index.

       The index is also capable of storing multiple entries (called "stages")
       for a given pathname. These stages are used to hold the various
       unmerged version of a file when a merge is in progress.

FURTHER DOCUMENTATION
       See the references in the "description" section to get started using
       Git. The following is probably more detail than necessary for a
       first-time user.

       The Git concepts chapter of the user-manual[2] and gitcore-tutorial(7)
       both provide introductions to the underlying Git architecture.

       See gitworkflows(7) for an overview of recommended workflows.

       See also the howto[3] documents for some useful examples.

       The internals are documented in the Git API documentation[4].

       Users migrating from CVS may also want to read gitcvs-migration(7).

AUTHORS
       Git was started by Linus Torvalds, and is currently maintained by Junio
       C Hamano. Numerous contributions have come from the Git mailing list
       <git@vger.kernel.org[5]>.
       http://www.openhub.net/p/git/contributors/summary gives you a more
       complete list of contributors.

       If you have a clone of git.git itself, the output of git-shortlog(1)
       and git-blame(1) can show you the authors for specific parts of the
       project.

REPORTING BUGS
       Report bugs to the Git mailing list <git@vger.kernel.org[5]> where the
       development and maintenance is primarily done. You do not have to be
       subscribed to the list to send a message there.

SEE ALSO
       gittutorial(7), gittutorial-2(7), giteveryday(7), gitcvs-migration(7),
       gitglossary(7), gitcore-tutorial(7), gitcli(7), The Git User's
       Manual[1], gitworkflows(7)

GIT
       Part of the git(1) suite

NOTES
        1. Git User's Manual
           git-htmldocs/user-manual.html

        2. Git concepts chapter of the user-manual
           git-htmldocs/user-manual.html#git-concepts

        3. howto
           git-htmldocs/howto-index.html

        4. Git API documentation
           git-htmldocs/technical/api-index.html

        5. git@vger.kernel.org
           mailto:git@vger.kernel.org

Git 2.7.0                         01/04/2016                            GIT(1)

GIT-CLONE(1)                      Git Manual                      GIT-CLONE(1)

NAME
       git-clone - Clone a repository into a new directory

SYNOPSIS
       git clone [--template=<template_directory>]
                 [-l] [-s] [--no-hardlinks] [-q] [-n] [--bare] [--mirror]
                 [-o <name>] [-b <name>] [-u <upload-pack>] [--reference <repository>]
                 [--dissociate] [--separate-git-dir <git dir>]
                 [--depth <depth>] [--[no-]single-branch]
                 [--recursive | --recurse-submodules] [--] <repository>
                 [<directory>]

DESCRIPTION
       Clones a repository into a newly created directory, creates
       remote-tracking branches for each branch in the cloned repository
       (visible using git branch -r), and creates and checks out an initial
       branch that is forked from the cloned repository's currently active
       branch.

       After the clone, a plain git fetch without arguments will update all
       the remote-tracking branches, and a git pull without arguments will in
       addition merge the remote master branch into the current master branch,
       if any (this is untrue when "--single-branch" is given; see below).

       This default configuration is achieved by creating references to the
       remote branch heads under refs/remotes/origin and by initializing
       remote.origin.url and remote.origin.fetch configuration variables.

OPTIONS
       --local, -l
           When the repository to clone from is on a local machine, this flag
           bypasses the normal "Git aware" transport mechanism and clones the
           repository by making a copy of HEAD and everything under objects
           and refs directories. The files under .git/objects/ directory are
           hardlinked to save space when possible.

           If the repository is specified as a local path (e.g.,
           /path/to/repo), this is the default, and --local is essentially a
           no-op. If the repository is specified as a URL, then this flag is
           ignored (and we never use the local optimizations). Specifying
           --no-local will override the default when /path/to/repo is given,
           using the regular Git transport instead.

       --no-hardlinks
           Force the cloning process from a repository on a local filesystem
           to copy the files under the .git/objects directory instead of using
           hardlinks. This may be desirable if you are trying to make a
           back-up of your repository.

       --shared, -s
           When the repository to clone is on the local machine, instead of
           using hard links, automatically setup .git/objects/info/alternates
           to share the objects with the source repository. The resulting
           repository starts out without any object of its own.

           NOTE: this is a possibly dangerous operation; do not use it unless
           you understand what it does. If you clone your repository using
           this option and then delete branches (or use any other Git command
           that makes any existing commit unreferenced) in the source
           repository, some objects may become unreferenced (or dangling).
           These objects may be removed by normal Git operations (such as git
           commit) which automatically call git gc --auto. (See git-gc(1).) If
           these objects are removed and were referenced by the cloned
           repository, then the cloned repository will become corrupt.

           Note that running git repack without the -l option in a repository
           cloned with -s will copy objects from the source repository into a
           pack in the cloned repository, removing the disk space savings of
           clone -s. It is safe, however, to run git gc, which uses the -l
           option by default.

           If you want to break the dependency of a repository cloned with -s
           on its source repository, you can simply run git repack -a to copy
           all objects from the source repository into a pack in the cloned
           repository.

       --reference <repository>
           If the reference repository is on the local machine, automatically
           setup .git/objects/info/alternates to obtain objects from the
           reference repository. Using an already existing repository as an
           alternate will require fewer objects to be copied from the
           repository being cloned, reducing network and local storage costs.

           NOTE: see the NOTE for the --shared option, and also the
           --dissociate option.

       --dissociate
           Borrow the objects from reference repositories specified with the
           --reference options only to reduce network transfer, and stop
           borrowing from them after a clone is made by making necessary local
           copies of borrowed objects. This option can also be used when
           cloning locally from a repository that already borrows objects from
           another repository--the new repository will borrow objects from the
           same repository, and this option can be used to stop the borrowing.

       --quiet, -q
           Operate quietly. Progress is not reported to the standard error
           stream. This flag is also passed to the `rsync' command when given.

       --verbose, -v
           Run verbosely. Does not affect the reporting of progress status to
           the standard error stream.

       --progress
           Progress status is reported on the standard error stream by default
           when it is attached to a terminal, unless -q is specified. This
           flag forces progress status even if the standard error stream is
           not directed to a terminal.

       --no-checkout, -n
           No checkout of HEAD is performed after the clone is complete.

       --bare
           Make a bare Git repository. That is, instead of creating
           <directory> and placing the administrative files in
           <directory>/.git, make the <directory> itself the $GIT_DIR. This
           obviously implies the -n because there is nowhere to check out the
           working tree. Also the branch heads at the remote are copied
           directly to corresponding local branch heads, without mapping them
           to refs/remotes/origin/. When this option is used, neither
           remote-tracking branches nor the related configuration variables
           are created.

       --mirror
           Set up a mirror of the source repository. This implies --bare.
           Compared to --bare, --mirror not only maps local branches of the
           source to local branches of the target, it maps all refs (including
           remote-tracking branches, notes etc.) and sets up a refspec
           configuration such that all these refs are overwritten by a git
           remote update in the target repository.

       --origin <name>, -o <name>
           Instead of using the remote name origin to keep track of the
           upstream repository, use <name>.

       --branch <name>, -b <name>
           Instead of pointing the newly created HEAD to the branch pointed to
           by the cloned repository's HEAD, point to <name> branch instead. In
           a non-bare repository, this is the branch that will be checked out.
           --branch can also take tags and detaches the HEAD at that commit in
           the resulting repository.

       --upload-pack <upload-pack>, -u <upload-pack>
           When given, and the repository to clone from is accessed via ssh,
           this specifies a non-default path for the command run on the other
           end.

       --template=<template_directory>
           Specify the directory from which templates will be used; (See the
           "TEMPLATE DIRECTORY" section of git-init(1).)

       --config <key>=<value>, -c <key>=<value>
           Set a configuration variable in the newly-created repository; this
           takes effect immediately after the repository is initialized, but
           before the remote history is fetched or any files checked out. The
           key is in the same format as expected by git-config(1) (e.g.,
           core.eol=true). If multiple values are given for the same key, each
           value will be written to the config file. This makes it safe, for
           example, to add additional fetch refspecs to the origin remote.

       --depth <depth>
           Create a shallow clone with a history truncated to the specified
           number of revisions.

       --[no-]single-branch
           Clone only the history leading to the tip of a single branch,
           either specified by the --branch option or the primary branch
           remote's HEAD points at. When creating a shallow clone with the
           --depth option, this is the default, unless --no-single-branch is
           given to fetch the histories near the tips of all branches. Further
           fetches into the resulting repository will only update the
           remote-tracking branch for the branch this option was used for the
           initial cloning. If the HEAD at the remote did not point at any
           branch when --single-branch clone was made, no remote-tracking
           branch is created.

       --recursive, --recurse-submodules
           After the clone is created, initialize all submodules within, using
           their default settings. This is equivalent to running git submodule
           update --init --recursive immediately after the clone is finished.
           This option is ignored if the cloned repository does not have a
           worktree/checkout (i.e. if any of --no-checkout/-n, --bare, or
           --mirror is given)

       --separate-git-dir=<git dir>
           Instead of placing the cloned repository where it is supposed to
           be, place the cloned repository at the specified directory, then
           make a filesystem-agnostic Git symbolic link to there. The result
           is Git repository can be separated from working tree.

       <repository>
           The (possibly remote) repository to clone from. See the URLS
           section below for more information on specifying repositories.

       <directory>
           The name of a new directory to clone into. The "humanish" part of
           the source repository is used if no directory is explicitly given
           (repo for /path/to/repo.git and foo for host.xz:foo/.git). Cloning
           into an existing directory is only allowed if the directory is
           empty.

GIT URLS
       In general, URLs contain information about the transport protocol, the
       address of the remote server, and the path to the repository. Depending
       on the transport protocol, some of this information may be absent.

       Git supports ssh, git, http, and https protocols (in addition, ftp, and
       ftps can be used for fetching and rsync can be used for fetching and
       pushing, but these are inefficient and deprecated; do not use them).

       The native transport (i.e. git:// URL) does no authentication and
       should be used with caution on unsecured networks.

       The following syntaxes may be used with them:

       o   ssh://[user@]host.xz[:port]/path/to/repo.git/

       o   git://host.xz[:port]/path/to/repo.git/

       o   http[s]://host.xz[:port]/path/to/repo.git/

       o   ftp[s]://host.xz[:port]/path/to/repo.git/

       o   rsync://host.xz/path/to/repo.git/

       An alternative scp-like syntax may also be used with the ssh protocol:

       o   [user@]host.xz:path/to/repo.git/

       This syntax is only recognized if there are no slashes before the first
       colon. This helps differentiate a local path that contains a colon. For
       example the local path foo:bar could be specified as an absolute path
       or ./foo:bar to avoid being misinterpreted as an ssh url.

       The ssh and git protocols additionally support ~username expansion:

       o   ssh://[user@]host.xz[:port]/~[user]/path/to/repo.git/

       o   git://host.xz[:port]/~[user]/path/to/repo.git/

       o   [user@]host.xz:/~[user]/path/to/repo.git/

       For local repositories, also supported by Git natively, the following
       syntaxes may be used:

       o   /path/to/repo.git/

       o   file:///path/to/repo.git/

       These two syntaxes are mostly equivalent, except the former implies
       --local option.

       When Git doesn't know how to handle a certain transport protocol, it
       attempts to use the remote-<transport> remote helper, if one exists. To
       explicitly request a remote helper, the following syntax may be used:

       o   <transport>::<address>

       where <address> may be a path, a server and path, or an arbitrary
       URL-like string recognized by the specific remote helper being invoked.
       See gitremote-helpers(1) for details.

       If there are a large number of similarly-named remote repositories and
       you want to use a different format for them (such that the URLs you use
       will be rewritten into URLs that work), you can create a configuration
       section of the form:

                   [url "<actual url base>"]
                           insteadOf = <other url base>

       For example, with this:

                   [url "git://git.host.xz/"]
                           insteadOf = host.xz:/path/to/
                           insteadOf = work:

       a URL like "work:repo.git" or like "host.xz:/path/to/repo.git" will be
       rewritten in any context that takes a URL to be
       "git://git.host.xz/repo.git".

       If you want to rewrite URLs for push only, you can create a
       configuration section of the form:

                   [url "<actual url base>"]
                           pushInsteadOf = <other url base>

       For example, with this:

                   [url "ssh://example.org/"]
                           pushInsteadOf = git://example.org/

       a URL like "git://example.org/path/to/repo.git" will be rewritten to
       "ssh://example.org/path/to/repo.git" for pushes, but pulls will still
       use the original URL.

EXAMPLES
       o   Clone from upstream:

               $ git clone git://git.kernel.org/pub/scm/.../linux.git my-linux
               $ cd my-linux
               $ make

       o   Make a local clone that borrows from the current directory, without
           checking things out:

               $ git clone -l -s -n . ../copy
               $ cd ../copy
               $ git show-branch

       o   Clone from upstream while borrowing from an existing local
           directory:

               $ git clone --reference /git/linux.git \
                       git://git.kernel.org/pub/scm/.../linux.git \
                       my-linux
               $ cd my-linux

       o   Create a bare repository to publish your changes to the public:

               $ git clone --bare -l /home/proj/.git /pub/scm/proj.git

GIT
       Part of the git(1) suite

Git 2.7.0                         01/04/2016                      GIT-CLONE(1)
peff commented 7 years ago

Individual exit codes and behaviors are documented in the various sub-commands, not in git(1). The usual convention of "exit 0 for success, non-zero for error" is assumed, and probably not explicitly laid out.

Error behavior and side effects should likewise be discussed in pages for individual sub-commands. So without a specific example of what you're looking for, it's hard to say whether it's there or not (and I can well believe there are a lot of cases that aren't documented well).

All that said, this is the issue tracker for the git-scm.com website, not git itself. While it does mirror the git manpages, you'd want to take specific questions upstream (to one of the venues at https://git-scm.com/community).

sxlijin commented 7 years ago

As @peff pointed out, there are individual man pages for Git, in large part due to the fact that (1) the git command itself is meaningless without a specific sub-command and (2) it's pretty much impossible to document everything in a single man page (nor would you want to!).

An excerpt from the man page for git fetch (also accessible at git-fetch):

OUTPUT
   The output of "git fetch" depends on the transport method used; this section
   describes the output when fetching over the Git protocol (either locally or via ssh)
   and Smart HTTP protocol.

   The status of the fetch is output in tabular form, with each line representing the
   status of a single ref. Each line is of the form:

        <flag> <summary> <from> -> <to> [<reason>]

   The status of up-to-date refs is shown only if the --verbose option is used.

   In compact output mode, specified with configuration variable fetch.output, if either
   entire <from> or <to> is found in the other string, it will be substituted with * in
   the other string. For example, master -> origin/master becomes master -> origin/*.

   flag
       A single character indicating the status of the ref:

       (space)
           for a successfully fetched fast-forward;

       +
           for a successful forced update;

       -
           for a successfully pruned ref;

       t
           for a successful tag update;

       *
           for a successfully fetched new ref;

       !
           for a ref that was rejected or failed to update; and

       =
           for a ref that was up to date and did not need fetching.

   summary
       For a successfully fetched ref, the summary shows the old and new values of the
       ref in a form suitable for using as an argument to git log (this is <old>..<new>
       in most cases, and <old>...<new> for forced non-fast-forward updates).

   from
       The name of the remote ref being fetched from, minus its refs/<type>/ prefix. In
       the case of deletion, the name of the remote ref is "(none)".

   to
       The name of the local ref being updated, minus its refs/<type>/ prefix.

   reason
       A human-readable explanation. In the case of successfully fetched refs, no
       explanation is needed. For a failed ref, the reason for failure is described.
andrewzhaosc commented 7 years ago

ok, but the man page you just posted doesn't mention anything about what happens in a network error. That's a big deal. What about a filesystem error. What if the git data is corrupt?

I don't just like the idea of "if something goes wrong, we'll tell you." This is especially shitty when scripting a git call, since a human readable explanation is totally useless.

In my previous comment I also included the man page for git clone tho, which doesn't even have an "output" section.

Sicaine commented 7 years ago

@andrewzhaosc Your 'wish' is not very specific. If you have specific stuff which is missing and you have a good proposal, that would be nice. If you do not want to do a lot of work upfront without knowing if it will get merged, you can do a small example and ask in a PR.

But personally, i do not document what happens in case of network issues, when the disk is full, hard drive issues and so on. For specific errors about git, which you can't find in the man pages, you might talk to the git guys. They have a mailing list git@vger.kernel.org

sxlijin commented 7 years ago

Moreover, those failure cases aren't Git's responsibility. It's not the 80's anymore: filesystems and networks are generally pretty decently reliable, and it would be absurd to handle those failure cases individually at the Git layer. In any case, if you really think this is important enough to be documented, you can chime in on the mailing list as linked above and talk to the core maintainers there.