fast fowards

GIT-PUSH(1)                   Git Manual                  GIT-PUSH(1)



NNAAMMEE
       git-push - Update remote refs along with associated objects

SSYYNNOOPPSSIISS
       _g_i_t _p_u_s_h [--all | --mirror | --tags] [--follow-tags] [--atomic] [-n | --dry-run] [--receive-pack=<git-receive-pack>]
                  [--repo=<repository>] [-f | --force] [-d | --delete] [--prune] [-v | --verbose]
                  [-u | --set-upstream] [--push-option=<string>]
                  [--[no-]signed|--sign=(true|false|if-asked)]
                  [--force-with-lease[=<refname>[:<expect>]]]
                  [--no-verify] [<repository> [<refspec>...]]


DDEESSCCRRIIPPTTIIOONN
       Updates remote refs using local refs, while sending objects
       necessary to complete the given refs.

       You can make interesting things happen to a repository every
       time you push into it, by setting up _h_o_o_k_s there. See
       documentation for ggiitt--rreecceeiivvee--ppaacckk(1).

       When the command line does not specify where to push with the
       <<rreeppoossiittoorryy>> argument, bbrraanncchh..**..rreemmoottee configuration for the
       current branch is consulted to determine where to push. If the
       configuration is missing, it defaults to _o_r_i_g_i_n.

       When the command line does not specify what to push with
       <<rreeffssppeecc>>...... arguments or ----aallll, ----mmiirrrroorr, ----ttaaggss options, the
       command finds the default <<rreeffssppeecc>> by consulting
       rreemmoottee..**..ppuusshh configuration, and if it is not found, honors
       ppuusshh..ddeeffaauulltt configuration to decide what to push (See ggiitt--
       ccoonnffiigg(1) for the meaning of ppuusshh..ddeeffaauulltt).

       When neither the command-line nor the configuration specify
       what to push, the default behavior is used, which corresponds
       to the ssiimmppllee value for ppuusshh..ddeeffaauulltt: the current branch is
       pushed to the corresponding upstream branch, but as a safety
       measure, the push is aborted if the upstream branch does not
       have the same name as the local one.

OOPPTTIIOONNSS
       <repository>
           The "remote" repository that is destination of a push
           operation. This parameter can be either a URL (see the
           section GIT URLS below) or the name of a remote (see the
           section REMOTES below).

       <refspec>...
           Specify what destination ref to update with what source
           object. The format of a <refspec> parameter is an optional
           plus ++, followed by the source object <src>, followed by a
           colon ::, followed by the destination ref <dst>.

           The <src> is often the name of the branch you would want
           to push, but it can be any arbitrary "SHA-1 expression",
           such as mmaasstteerr~~44 or HHEEAADD (see ggiittrreevviissiioonnss(7)).

           The <dst> tells which ref on the remote side is updated
           with this push. Arbitrary expressions cannot be used here,
           an actual ref must be named. If ggiitt ppuusshh [[<<rreeppoossiittoorryy>>]]
           without any <<rreeffssppeecc>> argument is set to update some ref
           at the destination with <<ssrrcc>> with
           rreemmoottee..<<rreeppoossiittoorryy>>..ppuusshh configuration variable, ::<<ddsstt>>
           part can be omitted—such a push will update a ref that
           <<ssrrcc>> normally updates without any <<rreeffssppeecc>> on the
           command line. Otherwise, missing ::<<ddsstt>> means to update
           the same ref as the <<ssrrcc>>.

           The object referenced by <src> is used to update the <dst>
           reference on the remote side. By default this is only
           allowed if <dst> is not a tag (annotated or lightweight),
           and then only if it can fast-forward <dst>. By having the
           optional leading ++, you can tell Git to update the <dst>
           ref even if it is not allowed by default (e.g., it is not
           a fast-forward.) This does nnoott attempt to merge <src> into
           <dst>. See EXAMPLES below for details.

           ttaagg <<ttaagg>> means the same as
           rreeffss//ttaaggss//<<ttaagg>>::rreeffss//ttaaggss//<<ttaagg>>.

           Pushing an empty <src> allows you to delete the <dst> ref
           from the remote repository.

           The special refspec :: (or ++:: to allow non-fast-forward
           updates) directs Git to push "matching" branches: for
           every branch that exists on the local side, the remote
           side is updated if a branch of the same name already
           exists on the remote side.

       --all
           Push all branches (i.e. refs under rreeffss//hheeaaddss//); cannot be
           used with other <refspec>.

       --prune
           Remove remote branches that don’t have a local
           counterpart. For example a remote branch ttmmpp will be
           removed if a local branch with the same name doesn’t exist
           any more. This also respects refspecs, e.g.  ggiitt ppuusshh
           ----pprruunnee rreemmoottee rreeffss//hheeaaddss//**::rreeffss//ttmmpp//** would make sure
           that remote rreeffss//ttmmpp//ffoooo will be removed if rreeffss//hheeaaddss//ffoooo
           doesn’t exist.

       --mirror
           Instead of naming each ref to push, specifies that all
           refs under rreeffss// (which includes but is not limited to
           rreeffss//hheeaaddss//, rreeffss//rreemmootteess//, and rreeffss//ttaaggss//) be mirrored to
           the remote repository. Newly created local refs will be
           pushed to the remote end, locally updated refs will be
           force updated on the remote end, and deleted refs will be
           removed from the remote end. This is the default if the
           configuration option rreemmoottee..<<rreemmoottee>>..mmiirrrroorr is set.

       -n, --dry-run
           Do everything except actually send the updates.

       --porcelain
           Produce machine-readable output. The output status line
           for each ref will be tab-separated and sent to stdout
           instead of stderr. The full symbolic names of the refs
           will be given.

       --delete
           All listed refs are deleted from the remote repository.
           This is the same as prefixing all refs with a colon.

       --tags
           All refs under rreeffss//ttaaggss are pushed, in addition to
           refspecs explicitly listed on the command line.

       --follow-tags
           Push all the refs that would be pushed without this
           option, and also push annotated tags in rreeffss//ttaaggss that are
           missing from the remote but are pointing at commit-ish
           that are reachable from the refs being pushed. This can
           also be specified with configuration variable
           ppuusshh..ffoolllloowwTTaaggss. For more information, see ppuusshh..ffoolllloowwTTaaggss
           in ggiitt--ccoonnffiigg(1).

       --[no-]signed, --sign=(true|false|if-asked)
           GPG-sign the push request to update refs on the receiving
           side, to allow it to be checked by the hooks and/or be
           logged. If ffaallssee or ----nnoo--ssiiggnneedd, no signing will be
           attempted. If ttrruuee or ----ssiiggnneedd, the push will fail if the
           server does not support signed pushes. If set to iiff--aasskkeedd,
           sign if and only if the server supports signed pushes. The
           push will also fail if the actual call to ggppgg ----ssiiggnn
           fails. See ggiitt--rreecceeiivvee--ppaacckk(1) for the details on the
           receiving end.

       --[no-]atomic
           Use an atomic transaction on the remote side if available.
           Either all refs are updated, or on error, no refs are
           updated. If the server does not support atomic pushes the
           push will fail.

       -o, --push-option
           Transmit the given string to the server, which passes them
           to the pre-receive as well as the post-receive hook. The
           given string must not contain a NUL or LF character.

       --receive-pack=<git-receive-pack>, --exec=<git-receive-pack>
           Path to the _g_i_t_-_r_e_c_e_i_v_e_-_p_a_c_k program on the remote end.
           Sometimes useful when pushing to a remote repository over
           ssh, and you do not have the program in a directory on the
           default $PATH.

       --[no-]force-with-lease, --force-with-lease=<refname>,
       --force-with-lease=<refname>:<expect>
           Usually, "git push" refuses to update a remote ref that is
           not an ancestor of the local ref used to overwrite it.

           This option overrides this restriction if the current
           value of the remote ref is the expected value. "git push"
           fails otherwise.

           Imagine that you have to rebase what you have already
           published. You will have to bypass the "must fast-forward"
           rule in order to replace the history you originally
           published with the rebased history. If somebody else built
           on top of your original history while you are rebasing,
           the tip of the branch at the remote may advance with her
           commit, and blindly pushing with ----ffoorrccee will lose her
           work.

           This option allows you to say that you expect the history
           you are updating is what you rebased and want to replace.
           If the remote ref still points at the commit you
           specified, you can be sure that no other people did
           anything to the ref. It is like taking a "lease" on the
           ref without explicitly locking it, and the remote ref is
           updated only if the "lease" is still valid.

           ----ffoorrccee--wwiitthh--lleeaassee alone, without specifying the details,
           will protect all remote refs that are going to be updated
           by requiring their current value to be the same as the
           remote-tracking branch we have for them.

           ----ffoorrccee--wwiitthh--lleeaassee==<<rreeffnnaammee>>, without specifying the
           expected value, will protect the named ref (alone), if it
           is going to be updated, by requiring its current value to
           be the same as the remote-tracking branch we have for it.

           ----ffoorrccee--wwiitthh--lleeaassee==<<rreeffnnaammee>>::<<eexxppeecctt>> will protect the
           named ref (alone), if it is going to be updated, by
           requiring its current value to be the same as the
           specified value <<eexxppeecctt>> (which is allowed to be different
           from the remote-tracking branch we have for the refname,
           or we do not even have to have such a remote-tracking
           branch when this form is used). If <<eexxppeecctt>> is the empty
           string, then the named ref must not already exist.

           Note that all forms other than
           ----ffoorrccee--wwiitthh--lleeaassee==<<rreeffnnaammee>>::<<eexxppeecctt>> that specifies the
           expected current value of the ref explicitly are still
           experimental and their semantics may change as we gain
           experience with this feature.

           "--no-force-with-lease" will cancel all the previous
           --force-with-lease on the command line.

           A general note on safety: supplying this option without an
           expected value, i.e. as ----ffoorrccee--wwiitthh--lleeaassee or
           ----ffoorrccee--wwiitthh--lleeaassee==<<rreeffnnaammee>> interacts very badly with
           anything that implicitly runs ggiitt ffeettcchh on the remote to
           be pushed to in the background, e.g.  ggiitt ffeettcchh oorriiggiinn on
           your repository in a cronjob.

           The protection it offers over ----ffoorrccee is ensuring that
           subsequent changes your work wasn’t based on aren’t
           clobbered, but this is trivially defeated if some
           background process is updating refs in the background. We
           don’t have anything except the remote tracking info to go
           by as a heuristic for refs you’re expected to have seen &
           are willing to clobber.

           If your editor or some other system is running ggiitt ffeettcchh
           in the background for you a way to mitigate this is to
           simply set up another remote:

               git remote add origin-push $(git config remote.origin.url)
               git fetch origin-push

           Now when the background process runs ggiitt ffeettcchh oorriiggiinn the
           references on oorriiggiinn--ppuusshh won’t be updated, and thus
           commands like:

               git push --force-with-lease origin-push

           Will fail unless you manually run ggiitt ffeettcchh oorriiggiinn--ppuusshh.
           This method is of course entirely defeated by something
           that runs ggiitt ffeettcchh ----aallll, in that case you’d need to
           either disable it or do something more tedious like:

               git fetch              # update 'master' from remote
               git tag base master    # mark our base point
               git rebase -i master   # rewrite some commits
               git push --force-with-lease=master:base master:master

           I.e. create a bbaassee tag for versions of the upstream code
           that you’ve seen and are willing to overwrite, then
           rewrite history, and finally force push changes to mmaasstteerr
           if the remote version is still at bbaassee, regardless of what
           your local rreemmootteess//oorriiggiinn//mmaasstteerr has been updated to in
           the background.

       -f, --force
           Usually, the command refuses to update a remote ref that
           is not an ancestor of the local ref used to overwrite it.
           Also, when ----ffoorrccee--wwiitthh--lleeaassee option is used, the command
           refuses to update a remote ref whose current value does
           not match what is expected.

           This flag disables these checks, and can cause the remote
           repository to lose commits; use it with care.

           Note that ----ffoorrccee applies to all the refs that are pushed,
           hence using it with ppuusshh..ddeeffaauulltt set to mmaattcchhiinngg or with
           multiple push destinations configured with rreemmoottee..**..ppuusshh
           may overwrite refs other than the current branch
           (including local refs that are strictly behind their
           remote counterpart). To force a push to only one branch,
           use a ++ in front of the refspec to push (e.g ggiitt ppuusshh
           oorriiggiinn ++mmaasstteerr to force a push to the mmaasstteerr branch). See
           the <<rreeffssppeecc>>......  section above for details.

       --repo=<repository>
           This option is equivalent to the <repository> argument. If
           both are specified, the command-line argument takes
           precedence.

       -u, --set-upstream
           For every branch that is up to date or successfully
           pushed, add upstream (tracking) reference, used by
           argument-less ggiitt--ppuullll(1) and other commands. For more
           information, see bbrraanncchh..<<nnaammee>>..mmeerrggee in ggiitt--ccoonnffiigg(1).

       --[no-]thin
           These options are passed to ggiitt--sseenndd--ppaacckk(1). A thin
           transfer significantly reduces the amount of sent data
           when the sender and receiver share many of the same
           objects in common. The default is --thin.

       -q, --quiet
           Suppress all output, including the listing of updated
           refs, unless an error occurs. Progress is not reported to
           the standard error stream.

       -v, --verbose
           Run verbosely.

       --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-recurse-submodules,
       --recurse-submodules=check|on-demand|only|no
           May be used to make sure all submodule commits used by the
           revisions to be pushed are available on a remote-tracking
           branch. If _c_h_e_c_k is used Git will verify that all
           submodule commits that changed in the revisions to be
           pushed are available on at least one remote of the
           submodule. If any commits are missing the push will be
           aborted and exit with non-zero status. If _o_n_-_d_e_m_a_n_d is
           used all submodules that changed in the revisions to be
           pushed will be pushed. If on-demand was not able to push
           all necessary revisions it will also be aborted and exit
           with non-zero status. If _o_n_l_y is used all submodules will
           be recursively pushed while the superproject is left
           unpushed. A value of _n_o or using ----nnoo--rreeccuurrssee--ssuubbmmoodduulleess
           can be used to override the push.recurseSubmodules
           configuration variable when no submodule recursion is
           required.

       --[no-]verify
           Toggle the pre-push hook (see ggiitthhooookkss(5)). The default is
           --verify, giving the hook a chance to prevent the push.
           With --no-verify, the hook is bypassed completely.

       -4, --ipv4
           Use IPv4 addresses only, ignoring IPv6 addresses.

       -6, --ipv6
           Use IPv6 addresses only, ignoring IPv4 addresses.

GGIITT UURRLLSS
       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, but this is
       inefficient and deprecated; do not use it).

       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:

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

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

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

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

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

       ·   [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 ffoooo::bbaarr could be
       specified as an absolute path or ..//ffoooo::bbaarr to avoid being
       misinterpreted as an ssh url.

       The ssh and git protocols additionally support ~username
       expansion:

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

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

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

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

       ·   /path/to/repo.git/

       ·   file:///path/to/repo.git/

       These two syntaxes are mostly equivalent, except when cloning,
       when the former implies --local option. See ggiitt--cclloonnee(1) for
       details.

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

       ·   <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 ggiittrreemmoottee--hheellppeerrss(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.

RREEMMOOTTEESS
       The name of one of the following can be used instead of a URL
       as <<rreeppoossiittoorryy>> argument:

       ·   a remote in the Git configuration file: $$GGIITT__DDIIRR//ccoonnffiigg,

       ·   a file in the $$GGIITT__DDIIRR//rreemmootteess directory, or

       ·   a file in the $$GGIITT__DDIIRR//bbrraanncchheess directory.

       All of these also allow you to omit the refspec from the
       command line because they each contain a refspec which git
       will use by default.

   NNaammeedd rreemmoottee iinn ccoonnffiigguurraattiioonn ffiillee
       You can choose to provide the name of a remote which you had
       previously configured using ggiitt--rreemmoottee(1), ggiitt--ccoonnffiigg(1) or
       even by a manual edit to the $$GGIITT__DDIIRR//ccoonnffiigg file. The URL of
       this remote will be used to access the repository. The refspec
       of this remote will be used by default when you do not provide
       a refspec on the command line. The entry in the config file
       would appear like this:

                   [remote "<name>"]
                           url = <url>
                           pushurl = <pushurl>
                           push = <refspec>
                           fetch = <refspec>


       The <<ppuusshhuurrll>> is used for pushes only. It is optional and
       defaults to <<uurrll>>.

   NNaammeedd ffiillee iinn $$GGIITT__DDIIRR//rreemmootteess
       You can choose to provide the name of a file in
       $$GGIITT__DDIIRR//rreemmootteess. The URL in this file will be used to access
       the repository. The refspec in this file will be used as
       default when you do not provide a refspec on the command line.
       This file should have the following format:

                   URL: one of the above URL format
                   Push: <refspec>
                   Pull: <refspec>


       PPuusshh:: lines are used by _g_i_t _p_u_s_h and PPuullll:: lines are used by
       _g_i_t _p_u_l_l and _g_i_t _f_e_t_c_h. Multiple PPuusshh:: and PPuullll:: lines may be
       specified for additional branch mappings.

   NNaammeedd ffiillee iinn $$GGIITT__DDIIRR//bbrraanncchheess
       You can choose to provide the name of a file in
       $$GGIITT__DDIIRR//bbrraanncchheess. The URL in this file will be used to access
       the repository. This file should have the following format:

                   <url>#<head>


       <<uurrll>> is required; ##<<hheeaadd>> is optional.

       Depending on the operation, git will use one of the following
       refspecs, if you don’t provide one on the command line.
       <<bbrraanncchh>> is the name of this file in $$GGIITT__DDIIRR//bbrraanncchheess and
       <<hheeaadd>> defaults to mmaasstteerr.

       git fetch uses:

                   refs/heads/<head>:refs/heads/<branch>


       git push uses:

                   HEAD:refs/heads/<head>


OOUUTTPPUUTT
       The output of "git push" depends on the transport method used;
       this section describes the output when pushing over the Git
       protocol (either locally or via ssh).

       The status of the push 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>)


       If --porcelain is used, then each line of the output is of the
       form:

            <flag> \t <from>:<to> \t <summary> (<reason>)


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

       flag
           A single character indicating the status of the ref:

           (space)
               for a successfully pushed fast-forward;

           ++
               for a successful forced update;

           --
               for a successfully deleted ref;

           **
               for a successfully pushed new ref;

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

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

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

           For a failed update, more details are given:

           rejected
               Git did not try to send the ref at all, typically
               because it is not a fast-forward and you did not force
               the update.

           remote rejected
               The remote end refused the update. Usually caused by a
               hook on the remote side, or because the remote
               repository has one of the following safety options in
               effect: rreecceeiivvee..ddeennyyCCuurrrreennttBBrraanncchh (for pushes to the
               checked out branch), rreecceeiivvee..ddeennyyNNoonnFFaassttFFoorrwwaarrddss (for
               forced non-fast-forward updates), rreecceeiivvee..ddeennyyDDeelleetteess
               or rreecceeiivvee..ddeennyyDDeelleetteeCCuurrrreenntt. See ggiitt--ccoonnffiigg(1).

           remote failure
               The remote end did not report the successful update of
               the ref, perhaps because of a temporary error on the
               remote side, a break in the network connection, or
               other transient error.

       from
           The name of the local ref being pushed, minus its
           rreeffss//<<ttyyppee>>// prefix. In the case of deletion, the name of
           the local ref is omitted.

       to
           The name of the remote ref being updated, minus its
           rreeffss//<<ttyyppee>>// prefix.

       reason
           A human-readable explanation. In the case of successfully
           pushed refs, no explanation is needed. For a failed ref,
           the reason for failure is described.

NNOOTTEE AABBOOUUTT FFAASSTT--FFOORRWWAARRDDSS
       When an update changes a branch (or more in general, a ref)
       that used to point at commit A to point at another commit B,
       it is called a fast-forward update if and only if B is a
       descendant of A.

       In a fast-forward update from A to B, the set of commits that
       the original commit A built on top of is a subset of the
       commits the new commit B builds on top of. Hence, it does not
       lose any history.

       In contrast, a non-fast-forward update will lose history. For
       example, suppose you and somebody else started at the same
       commit X, and you built a history leading to commit B while
       the other person built a history leading to commit A. The
       history looks like this:

                 B
                /
            ---X---A


       Further suppose that the other person already pushed changes
       leading to A back to the original repository from which you
       two obtained the original commit X.

       The push done by the other person updated the branch that used
       to point at commit X to point at commit A. It is a
       fast-forward.

       But if you try to push, you will attempt to update the branch
       (that now points at A) with commit B. This does _n_o_t
       fast-forward. If you did so, the changes introduced by commit
       A will be lost, because everybody will now start building on
       top of B.

       The command by default does not allow an update that is not a
       fast-forward to prevent such loss of history.

       If you do not want to lose your work (history from X to B) or
       the work by the other person (history from X to A), you would
       need to first fetch the history from the repository, create a
       history that contains changes done by both parties, and push
       the result back.

       You can perform "git pull", resolve potential conflicts, and
       "git push" the result. A "git pull" will create a merge commit
       C between commits A and B.

                 B---C
                /   /
            ---X---A


       Updating A with the resulting merge commit will fast-forward
       and your push will be accepted.

       Alternatively, you can rebase your change between X and B on
       top of A, with "git pull --rebase", and push the result back.
       The rebase will create a new commit D that builds the change
       between X and B on top of A.

                 B   D
                /   /
            ---X---A


       Again, updating A with this commit will fast-forward and your
       push will be accepted.

       There is another common situation where you may encounter
       non-fast-forward rejection when you try to push, and it is
       possible even when you are pushing into a repository nobody
       else pushes into. After you push commit A yourself (in the
       first picture in this section), replace it with "git commit
       --amend" to produce commit B, and you try to push it out,
       because forgot that you have pushed A out already. In such a
       case, and only if you are certain that nobody in the meantime
       fetched your earlier commit A (and started building on top of
       it), you can run "git push --force" to overwrite it. In other
       words, "git push --force" is a method reserved for a case
       where you do mean to lose history.

EEXXAAMMPPLLEESS
       ggiitt ppuusshh
           Works like ggiitt ppuusshh <<rreemmoottee>>, where <remote> is the
           current branch’s remote (or oorriiggiinn, if no remote is
           configured for the current branch).

       ggiitt ppuusshh oorriiggiinn
           Without additional configuration, pushes the current
           branch to the configured upstream (rreemmoottee..oorriiggiinn..mmeerrggee
           configuration variable) if it has the same name as the
           current branch, and errors out without pushing otherwise.

           The default behavior of this command when no <refspec> is
           given can be configured by setting the ppuusshh option of the
           remote, or the ppuusshh..ddeeffaauulltt configuration variable.

           For example, to default to pushing only the current branch
           to oorriiggiinn use ggiitt ccoonnffiigg rreemmoottee..oorriiggiinn..ppuusshh HHEEAADD. Any
           valid <refspec> (like the ones in the examples below) can
           be configured as the default for ggiitt ppuusshh oorriiggiinn.

       ggiitt ppuusshh oorriiggiinn ::
           Push "matching" branches to oorriiggiinn. See <refspec> in the
           OPTIONS section above for a description of "matching"
           branches.

       ggiitt ppuusshh oorriiggiinn mmaasstteerr
           Find a ref that matches mmaasstteerr in the source repository
           (most likely, it would find rreeffss//hheeaaddss//mmaasstteerr), and update
           the same ref (e.g.  rreeffss//hheeaaddss//mmaasstteerr) in oorriiggiinn
           repository with it. If mmaasstteerr did not exist remotely, it
           would be created.

       ggiitt ppuusshh oorriiggiinn HHEEAADD
           A handy way to push the current branch to the same name on
           the remote.

       ggiitt ppuusshh mmootthheerrsshhiipp mmaasstteerr::ssaatteelllliittee//mmaasstteerr ddeevv::ssaatteelllliittee//ddeevv
           Use the source ref that matches mmaasstteerr (e.g.
           rreeffss//hheeaaddss//mmaasstteerr) to update the ref that matches
           ssaatteelllliittee//mmaasstteerr (most probably
           rreeffss//rreemmootteess//ssaatteelllliittee//mmaasstteerr) in the mmootthheerrsshhiipp
           repository; do the same for ddeevv and ssaatteelllliittee//ddeevv.

           This is to emulate ggiitt ffeettcchh run on the mmootthheerrsshhiipp using
           ggiitt ppuusshh that is run in the opposite direction in order to
           integrate the work done on ssaatteelllliittee, and is often
           necessary when you can only make connection in one way
           (i.e. satellite can ssh into mothership but mothership
           cannot initiate connection to satellite because the latter
           is behind a firewall or does not run sshd).

           After running this ggiitt ppuusshh on the ssaatteelllliittee machine, you
           would ssh into the mmootthheerrsshhiipp and run ggiitt mmeerrggee there to
           complete the emulation of ggiitt ppuullll that were run on
           mmootthheerrsshhiipp to pull changes made on ssaatteelllliittee.

       ggiitt ppuusshh oorriiggiinn HHEEAADD::mmaasstteerr
           Push the current branch to the remote ref matching mmaasstteerr
           in the oorriiggiinn repository. This form is convenient to push
           the current branch without thinking about its local name.

       ggiitt ppuusshh oorriiggiinn mmaasstteerr::rreeffss//hheeaaddss//eexxppeerriimmeennttaall
           Create the branch eexxppeerriimmeennttaall in the oorriiggiinn repository by
           copying the current mmaasstteerr branch. This form is only
           needed to create a new branch or tag in the remote
           repository when the local name and the remote name are
           different; otherwise, the ref name on its own will work.

       ggiitt ppuusshh oorriiggiinn ::eexxppeerriimmeennttaall
           Find a ref that matches eexxppeerriimmeennttaall in the oorriiggiinn
           repository (e.g.  rreeffss//hheeaaddss//eexxppeerriimmeennttaall), and delete it.

       ggiitt ppuusshh oorriiggiinn ++ddeevv::mmaasstteerr
           Update the origin repository’s master branch with the dev
           branch, allowing non-fast-forward updates.  TThhiiss ccaann lleeaavvee
           uunnrreeffeerreenncceedd ccoommmmiittss ddaanngglliinngg iinn tthhee oorriiggiinn rreeppoossiittoorryy..
           Consider the following situation, where a fast-forward is
           not possible:

                           o---o---o---A---B  origin/master
                                    \
                                     X---Y---Z  dev

           The above command would change the origin repository to

                                     A---B  (unnamed branch)
                                    /
                           o---o---o---X---Y---Z  master

           Commits A and B would no longer belong to a branch with a
           symbolic name, and so would be unreachable. As such, these
           commits would be removed by a ggiitt ggcc command on the origin
           repository.

SSEECCUURRIITTYY
       The fetch and push protocols are not designed to prevent one
       side from stealing data from the other repository that was not
       intended to be shared. If you have private data that you need
       to protect from a malicious peer, your best option is to store
       it in another repository. This applies to both clients and
       servers. In particular, namespaces on a server are not
       effective for read access control; you should only grant read
       access to a namespace to clients that you would trust with
       read access to the entire repository.

       The known attack vectors are as follows:

        1. The victim sends "have" lines advertising the IDs of
           objects it has that are not explicitly intended to be
           shared but can be used to optimize the transfer if the
           peer also has them. The attacker chooses an object ID X to
           steal and sends a ref to X, but isn’t required to send the
           content of X because the victim already has it. Now the
           victim believes that the attacker has X, and it sends the
           content of X back to the attacker later. (This attack is
           most straightforward for a client to perform on a server,
           by creating a ref to X in the namespace the client has
           access to and then fetching it. The most likely way for a
           server to perform it on a client is to "merge" X into a
           public branch and hope that the user does additional work
           on this branch and pushes it back to the server without
           noticing the merge.)

        2. As in #1, the attacker chooses an object ID X to steal.
           The victim sends an object Y that the attacker already
           has, and the attacker falsely claims to have X and not Y,
           so the victim sends Y as a delta against X. The delta
           reveals regions of X that are similar to Y to the
           attacker.

GGIITT
       Part of the ggiitt(1) suite



Git 2.14.1                    08/10/2017                  GIT-PUSH(1)