Documentation / git-push.txton commit general improvements (43abf13)
   1git-push(1)
   2===========
   3
   4NAME
   5----
   6git-push - Update remote refs along with associated objects
   7
   8
   9SYNOPSIS
  10--------
  11[verse]
  12'git push' [--all | --mirror | --tags] [--follow-tags] [--atomic] [-n | --dry-run] [--receive-pack=<git-receive-pack>]
  13           [--repo=<repository>] [-f | --force] [-d | --delete] [--prune] [-v | --verbose]
  14           [-u | --set-upstream] [-o <string> | --push-option=<string>]
  15           [--[no-]signed|--signed=(true|false|if-asked)]
  16           [--force-with-lease[=<refname>[:<expect>]]]
  17           [--no-verify] [<repository> [<refspec>...]]
  18
  19DESCRIPTION
  20-----------
  21
  22Updates remote refs using local refs, while sending objects
  23necessary to complete the given refs.
  24
  25You can make interesting things happen to a repository
  26every time you push into it, by setting up 'hooks' there.  See
  27documentation for linkgit:git-receive-pack[1].
  28
  29When the command line does not specify where to push with the
  30`<repository>` argument, `branch.*.remote` configuration for the
  31current branch is consulted to determine where to push.  If the
  32configuration is missing, it defaults to 'origin'.
  33
  34When the command line does not specify what to push with `<refspec>...`
  35arguments or `--all`, `--mirror`, `--tags` options, the command finds
  36the default `<refspec>` by consulting `remote.*.push` configuration,
  37and if it is not found, honors `push.default` configuration to decide
  38what to push (See linkgit:git-config[1] for the meaning of `push.default`).
  39
  40When neither the command-line nor the configuration specify what to
  41push, the default behavior is used, which corresponds to the `simple`
  42value for `push.default`: the current branch is pushed to the
  43corresponding upstream branch, but as a safety measure, the push is
  44aborted if the upstream branch does not have the same name as the
  45local one.
  46
  47
  48OPTIONS[[OPTIONS]]
  49------------------
  50<repository>::
  51        The "remote" repository that is destination of a push
  52        operation.  This parameter can be either a URL
  53        (see the section <<URLS,GIT URLS>> below) or the name
  54        of a remote (see the section <<REMOTES,REMOTES>> below).
  55
  56<refspec>...::
  57        Specify what destination ref to update with what source object.
  58        The format of a <refspec> parameter is an optional plus
  59        `+`, followed by the source object <src>, followed
  60        by a colon `:`, followed by the destination ref <dst>.
  61+
  62The <src> is often the name of the branch you would want to push, but
  63it can be any arbitrary "SHA-1 expression", such as `master~4` or
  64`HEAD` (see linkgit:gitrevisions[7]).
  65+
  66The <dst> tells which ref on the remote side is updated with this
  67push. Arbitrary expressions cannot be used here, an actual ref must
  68be named.
  69If `git push [<repository>]` without any `<refspec>` argument is set to
  70update some ref at the destination with `<src>` with
  71`remote.<repository>.push` configuration variable, `:<dst>` part can
  72be omitted--such a push will update a ref that `<src>` normally updates
  73without any `<refspec>` on the command line.  Otherwise, missing
  74`:<dst>` means to update the same ref as the `<src>`.
  75+
  76If <dst> doesn't start with `refs/` (e.g. `refs/heads/master`) we will
  77try to infer where in `refs/*` on the destination <repository> it
  78belongs based on the type of <src> being pushed and whether <dst>
  79is ambiguous.
  80+
  81--
  82* If <dst> unambiguously refers to a ref on the <repository> remote,
  83  then push to that ref.
  84
  85* If <src> resolves to a ref starting with refs/heads/ or refs/tags/,
  86  then prepend that to <dst>.
  87
  88* Other ambiguity resolutions might be added in the future, but for
  89  now any other cases will error out with an error indicating what we
  90  tried, and depending on the `advice.pushUnqualifiedRefname`
  91  configuration (see linkgit:git-config[1]) suggest what refs/
  92  namespace you may have wanted to push to.
  93
  94--
  95+
  96The object referenced by <src> is used to update the <dst> reference
  97on the remote side. Whether this is allowed depends on where in
  98`refs/*` the <dst> reference lives as described in detail below, in
  99those sections "update" means any modifications except deletes, which
 100as noted after the next few sections are treated differently.
 101+
 102The `refs/heads/*` namespace will only accept commit objects, and
 103updates only if they can be fast-forwarded.
 104+
 105The `refs/tags/*` namespace will accept any kind of object (as
 106commits, trees and blobs can be tagged), and any updates to them will
 107be rejected.
 108+
 109It's possible to push any type of object to any namespace outside of
 110`refs/{tags,heads}/*`. In the case of tags and commits, these will be
 111treated as if they were the commits inside `refs/heads/*` for the
 112purposes of whether the update is allowed.
 113+
 114I.e. a fast-forward of commits and tags outside `refs/{tags,heads}/*`
 115is allowed, even in cases where what's being fast-forwarded is not a
 116commit, but a tag object which happens to point to a new commit which
 117is a fast-forward of the commit the last tag (or commit) it's
 118replacing. Replacing a tag with an entirely different tag is also
 119allowed, if it points to the same commit, as well as pushing a peeled
 120tag, i.e. pushing the commit that existing tag object points to, or a
 121new tag object which an existing commit points to.
 122+
 123Tree and blob objects outside of `refs/{tags,heads}/*` will be treated
 124the same way as if they were inside `refs/tags/*`, any update of them
 125will be rejected.
 126+
 127All of the rules described above about what's not allowed as an update
 128can be overridden by adding an the optional leading `+` to a refspec
 129(or using `--force` command line option). The only exception to this
 130is that no amount of forcing will make the `refs/heads/*` namespace
 131accept a non-commit object. Hooks and configuration can also override
 132or amend these rules, see e.g. `receive.denyNonFastForwards` in
 133linkgit:git-config[1] and `pre-receive` and `update` in
 134linkgit:githooks[5].
 135+
 136Pushing an empty <src> allows you to delete the <dst> ref from the
 137remote repository. Deletions are always accepted without a leading `+`
 138in the refspec (or `--force`), except when forbidden by configuration
 139or hooks. See `receive.denyDeletes` in linkgit:git-config[1] and
 140`pre-receive` and `update` in linkgit:githooks[5].
 141+
 142The special refspec `:` (or `+:` to allow non-fast-forward updates)
 143directs Git to push "matching" branches: for every branch that exists on
 144the local side, the remote side is updated if a branch of the same name
 145already exists on the remote side.
 146+
 147`tag <tag>` means the same as `refs/tags/<tag>:refs/tags/<tag>`.
 148
 149--all::
 150        Push all branches (i.e. refs under `refs/heads/`); cannot be
 151        used with other <refspec>.
 152
 153--prune::
 154        Remove remote branches that don't have a local counterpart. For example
 155        a remote branch `tmp` will be removed if a local branch with the same
 156        name doesn't exist any more. This also respects refspecs, e.g.
 157        `git push --prune remote refs/heads/*:refs/tmp/*` would
 158        make sure that remote `refs/tmp/foo` will be removed if `refs/heads/foo`
 159        doesn't exist.
 160
 161--mirror::
 162        Instead of naming each ref to push, specifies that all
 163        refs under `refs/` (which includes but is not
 164        limited to `refs/heads/`, `refs/remotes/`, and `refs/tags/`)
 165        be mirrored to the remote repository.  Newly created local
 166        refs will be pushed to the remote end, locally updated refs
 167        will be force updated on the remote end, and deleted refs
 168        will be removed from the remote end.  This is the default
 169        if the configuration option `remote.<remote>.mirror` is
 170        set.
 171
 172-n::
 173--dry-run::
 174        Do everything except actually send the updates.
 175
 176--porcelain::
 177        Produce machine-readable output.  The output status line for each ref
 178        will be tab-separated and sent to stdout instead of stderr.  The full
 179        symbolic names of the refs will be given.
 180
 181-d::
 182--delete::
 183        All listed refs are deleted from the remote repository. This is
 184        the same as prefixing all refs with a colon.
 185
 186--tags::
 187        All refs under `refs/tags` are pushed, in
 188        addition to refspecs explicitly listed on the command
 189        line.
 190
 191--follow-tags::
 192        Push all the refs that would be pushed without this option,
 193        and also push annotated tags in `refs/tags` that are missing
 194        from the remote but are pointing at commit-ish that are
 195        reachable from the refs being pushed.  This can also be specified
 196        with configuration variable `push.followTags`.  For more
 197        information, see `push.followTags` in linkgit:git-config[1].
 198
 199--[no-]signed::
 200--signed=(true|false|if-asked)::
 201        GPG-sign the push request to update refs on the receiving
 202        side, to allow it to be checked by the hooks and/or be
 203        logged.  If `false` or `--no-signed`, no signing will be
 204        attempted.  If `true` or `--signed`, the push will fail if the
 205        server does not support signed pushes.  If set to `if-asked`,
 206        sign if and only if the server supports signed pushes.  The push
 207        will also fail if the actual call to `gpg --sign` fails.  See
 208        linkgit:git-receive-pack[1] for the details on the receiving end.
 209
 210--[no-]atomic::
 211        Use an atomic transaction on the remote side if available.
 212        Either all refs are updated, or on error, no refs are updated.
 213        If the server does not support atomic pushes the push will fail.
 214
 215-o <option>::
 216--push-option=<option>::
 217        Transmit the given string to the server, which passes them to
 218        the pre-receive as well as the post-receive hook. The given string
 219        must not contain a NUL or LF character.
 220        When multiple `--push-option=<option>` are given, they are
 221        all sent to the other side in the order listed on the
 222        command line.
 223        When no `--push-option=<option>` is given from the command
 224        line, the values of configuration variable `push.pushOption`
 225        are used instead.
 226
 227--receive-pack=<git-receive-pack>::
 228--exec=<git-receive-pack>::
 229        Path to the 'git-receive-pack' program on the remote
 230        end.  Sometimes useful when pushing to a remote
 231        repository over ssh, and you do not have the program in
 232        a directory on the default $PATH.
 233
 234--[no-]force-with-lease::
 235--force-with-lease=<refname>::
 236--force-with-lease=<refname>:<expect>::
 237        Usually, "git push" refuses to update a remote ref that is
 238        not an ancestor of the local ref used to overwrite it.
 239+
 240This option overrides this restriction if the current value of the
 241remote ref is the expected value.  "git push" fails otherwise.
 242+
 243Imagine that you have to rebase what you have already published.
 244You will have to bypass the "must fast-forward" rule in order to
 245replace the history you originally published with the rebased history.
 246If somebody else built on top of your original history while you are
 247rebasing, the tip of the branch at the remote may advance with her
 248commit, and blindly pushing with `--force` will lose her work.
 249+
 250This option allows you to say that you expect the history you are
 251updating is what you rebased and want to replace. If the remote ref
 252still points at the commit you specified, you can be sure that no
 253other people did anything to the ref. It is like taking a "lease" on
 254the ref without explicitly locking it, and the remote ref is updated
 255only if the "lease" is still valid.
 256+
 257`--force-with-lease` alone, without specifying the details, will protect
 258all remote refs that are going to be updated by requiring their
 259current value to be the same as the remote-tracking branch we have
 260for them.
 261+
 262`--force-with-lease=<refname>`, without specifying the expected value, will
 263protect the named ref (alone), if it is going to be updated, by
 264requiring its current value to be the same as the remote-tracking
 265branch we have for it.
 266+
 267`--force-with-lease=<refname>:<expect>` will protect the named ref (alone),
 268if it is going to be updated, by requiring its current value to be
 269the same as the specified value `<expect>` (which is allowed to be
 270different from the remote-tracking branch we have for the refname,
 271or we do not even have to have such a remote-tracking branch when
 272this form is used).  If `<expect>` is the empty string, then the named ref
 273must not already exist.
 274+
 275Note that all forms other than `--force-with-lease=<refname>:<expect>`
 276that specifies the expected current value of the ref explicitly are
 277still experimental and their semantics may change as we gain experience
 278with this feature.
 279+
 280"--no-force-with-lease" will cancel all the previous --force-with-lease on the
 281command line.
 282+
 283A general note on safety: supplying this option without an expected
 284value, i.e. as `--force-with-lease` or `--force-with-lease=<refname>`
 285interacts very badly with anything that implicitly runs `git fetch` on
 286the remote to be pushed to in the background, e.g. `git fetch origin`
 287on your repository in a cronjob.
 288+
 289The protection it offers over `--force` is ensuring that subsequent
 290changes your work wasn't based on aren't clobbered, but this is
 291trivially defeated if some background process is updating refs in the
 292background. We don't have anything except the remote tracking info to
 293go by as a heuristic for refs you're expected to have seen & are
 294willing to clobber.
 295+
 296If your editor or some other system is running `git fetch` in the
 297background for you a way to mitigate this is to simply set up another
 298remote:
 299+
 300        git remote add origin-push $(git config remote.origin.url)
 301        git fetch origin-push
 302+
 303Now when the background process runs `git fetch origin` the references
 304on `origin-push` won't be updated, and thus commands like:
 305+
 306        git push --force-with-lease origin-push
 307+
 308Will fail unless you manually run `git fetch origin-push`. This method
 309is of course entirely defeated by something that runs `git fetch
 310--all`, in that case you'd need to either disable it or do something
 311more tedious like:
 312+
 313        git fetch              # update 'master' from remote
 314        git tag base master    # mark our base point
 315        git rebase -i master   # rewrite some commits
 316        git push --force-with-lease=master:base master:master
 317+
 318I.e. create a `base` tag for versions of the upstream code that you've
 319seen and are willing to overwrite, then rewrite history, and finally
 320force push changes to `master` if the remote version is still at
 321`base`, regardless of what your local `remotes/origin/master` has been
 322updated to in the background.
 323
 324-f::
 325--force::
 326        Usually, the command refuses to update a remote ref that is
 327        not an ancestor of the local ref used to overwrite it.
 328        Also, when `--force-with-lease` option is used, the command refuses
 329        to update a remote ref whose current value does not match
 330        what is expected.
 331+
 332This flag disables these checks, and can cause the remote repository
 333to lose commits; use it with care.
 334+
 335Note that `--force` applies to all the refs that are pushed, hence
 336using it with `push.default` set to `matching` or with multiple push
 337destinations configured with `remote.*.push` may overwrite refs
 338other than the current branch (including local refs that are
 339strictly behind their remote counterpart).  To force a push to only
 340one branch, use a `+` in front of the refspec to push (e.g `git push
 341origin +master` to force a push to the `master` branch). See the
 342`<refspec>...` section above for details.
 343
 344--repo=<repository>::
 345        This option is equivalent to the <repository> argument. If both
 346        are specified, the command-line argument takes precedence.
 347
 348-u::
 349--set-upstream::
 350        For every branch that is up to date or successfully pushed, add
 351        upstream (tracking) reference, used by argument-less
 352        linkgit:git-pull[1] and other commands. For more information,
 353        see `branch.<name>.merge` in linkgit:git-config[1].
 354
 355--[no-]thin::
 356        These options are passed to linkgit:git-send-pack[1]. A thin transfer
 357        significantly reduces the amount of sent data when the sender and
 358        receiver share many of the same objects in common. The default is
 359        `--thin`.
 360
 361-q::
 362--quiet::
 363        Suppress all output, including the listing of updated refs,
 364        unless an error occurs. Progress is not reported to the standard
 365        error stream.
 366
 367-v::
 368--verbose::
 369        Run verbosely.
 370
 371--progress::
 372        Progress status is reported on the standard error stream
 373        by default when it is attached to a terminal, unless -q
 374        is specified. This flag forces progress status even if the
 375        standard error stream is not directed to a terminal.
 376
 377--no-recurse-submodules::
 378--recurse-submodules=check|on-demand|only|no::
 379        May be used to make sure all submodule commits used by the
 380        revisions to be pushed are available on a remote-tracking branch.
 381        If 'check' is used Git will verify that all submodule commits that
 382        changed in the revisions to be pushed are available on at least one
 383        remote of the submodule. If any commits are missing the push will
 384        be aborted and exit with non-zero status. If 'on-demand' is used
 385        all submodules that changed in the revisions to be pushed will be
 386        pushed. If on-demand was not able to push all necessary revisions it will
 387        also be aborted and exit with non-zero status. If 'only' is used all
 388        submodules will be recursively pushed while the superproject is left
 389        unpushed. A value of 'no' or using `--no-recurse-submodules` can be used
 390        to override the push.recurseSubmodules configuration variable when no
 391        submodule recursion is required.
 392
 393--[no-]verify::
 394        Toggle the pre-push hook (see linkgit:githooks[5]).  The
 395        default is --verify, giving the hook a chance to prevent the
 396        push.  With --no-verify, the hook is bypassed completely.
 397
 398-4::
 399--ipv4::
 400        Use IPv4 addresses only, ignoring IPv6 addresses.
 401
 402-6::
 403--ipv6::
 404        Use IPv6 addresses only, ignoring IPv4 addresses.
 405
 406include::urls-remotes.txt[]
 407
 408OUTPUT
 409------
 410
 411The output of "git push" depends on the transport method used; this
 412section describes the output when pushing over the Git protocol (either
 413locally or via ssh).
 414
 415The status of the push is output in tabular form, with each line
 416representing the status of a single ref. Each line is of the form:
 417
 418-------------------------------
 419 <flag> <summary> <from> -> <to> (<reason>)
 420-------------------------------
 421
 422If --porcelain is used, then each line of the output is of the form:
 423
 424-------------------------------
 425 <flag> \t <from>:<to> \t <summary> (<reason>)
 426-------------------------------
 427
 428The status of up-to-date refs is shown only if --porcelain or --verbose
 429option is used.
 430
 431flag::
 432        A single character indicating the status of the ref:
 433(space);; for a successfully pushed fast-forward;
 434`+`;; for a successful forced update;
 435`-`;; for a successfully deleted ref;
 436`*`;; for a successfully pushed new ref;
 437`!`;; for a ref that was rejected or failed to push; and
 438`=`;; for a ref that was up to date and did not need pushing.
 439
 440summary::
 441        For a successfully pushed ref, the summary shows the old and new
 442        values of the ref in a form suitable for using as an argument to
 443        `git log` (this is `<old>..<new>` in most cases, and
 444        `<old>...<new>` for forced non-fast-forward updates).
 445+
 446For a failed update, more details are given:
 447+
 448--
 449rejected::
 450        Git did not try to send the ref at all, typically because it
 451        is not a fast-forward and you did not force the update.
 452
 453remote rejected::
 454        The remote end refused the update.  Usually caused by a hook
 455        on the remote side, or because the remote repository has one
 456        of the following safety options in effect:
 457        `receive.denyCurrentBranch` (for pushes to the checked out
 458        branch), `receive.denyNonFastForwards` (for forced
 459        non-fast-forward updates), `receive.denyDeletes` or
 460        `receive.denyDeleteCurrent`.  See linkgit:git-config[1].
 461
 462remote failure::
 463        The remote end did not report the successful update of the ref,
 464        perhaps because of a temporary error on the remote side, a
 465        break in the network connection, or other transient error.
 466--
 467
 468from::
 469        The name of the local ref being pushed, minus its
 470        `refs/<type>/` prefix. In the case of deletion, the
 471        name of the local ref is omitted.
 472
 473to::
 474        The name of the remote ref being updated, minus its
 475        `refs/<type>/` prefix.
 476
 477reason::
 478        A human-readable explanation. In the case of successfully pushed
 479        refs, no explanation is needed. For a failed ref, the reason for
 480        failure is described.
 481
 482NOTE ABOUT FAST-FORWARDS
 483------------------------
 484
 485When an update changes a branch (or more in general, a ref) that used to
 486point at commit A to point at another commit B, it is called a
 487fast-forward update if and only if B is a descendant of A.
 488
 489In a fast-forward update from A to B, the set of commits that the original
 490commit A built on top of is a subset of the commits the new commit B
 491builds on top of.  Hence, it does not lose any history.
 492
 493In contrast, a non-fast-forward update will lose history.  For example,
 494suppose you and somebody else started at the same commit X, and you built
 495a history leading to commit B while the other person built a history
 496leading to commit A.  The history looks like this:
 497
 498----------------
 499
 500      B
 501     /
 502 ---X---A
 503
 504----------------
 505
 506Further suppose that the other person already pushed changes leading to A
 507back to the original repository from which you two obtained the original
 508commit X.
 509
 510The push done by the other person updated the branch that used to point at
 511commit X to point at commit A.  It is a fast-forward.
 512
 513But if you try to push, you will attempt to update the branch (that
 514now points at A) with commit B.  This does _not_ fast-forward.  If you did
 515so, the changes introduced by commit A will be lost, because everybody
 516will now start building on top of B.
 517
 518The command by default does not allow an update that is not a fast-forward
 519to prevent such loss of history.
 520
 521If you do not want to lose your work (history from X to B) or the work by
 522the other person (history from X to A), you would need to first fetch the
 523history from the repository, create a history that contains changes done
 524by both parties, and push the result back.
 525
 526You can perform "git pull", resolve potential conflicts, and "git push"
 527the result.  A "git pull" will create a merge commit C between commits A
 528and B.
 529
 530----------------
 531
 532      B---C
 533     /   /
 534 ---X---A
 535
 536----------------
 537
 538Updating A with the resulting merge commit will fast-forward and your
 539push will be accepted.
 540
 541Alternatively, you can rebase your change between X and B on top of A,
 542with "git pull --rebase", and push the result back.  The rebase will
 543create a new commit D that builds the change between X and B on top of
 544A.
 545
 546----------------
 547
 548      B   D
 549     /   /
 550 ---X---A
 551
 552----------------
 553
 554Again, updating A with this commit will fast-forward and your push will be
 555accepted.
 556
 557There is another common situation where you may encounter non-fast-forward
 558rejection when you try to push, and it is possible even when you are
 559pushing into a repository nobody else pushes into. After you push commit
 560A yourself (in the first picture in this section), replace it with "git
 561commit --amend" to produce commit B, and you try to push it out, because
 562forgot that you have pushed A out already. In such a case, and only if
 563you are certain that nobody in the meantime fetched your earlier commit A
 564(and started building on top of it), you can run "git push --force" to
 565overwrite it. In other words, "git push --force" is a method reserved for
 566a case where you do mean to lose history.
 567
 568
 569EXAMPLES
 570--------
 571
 572`git push`::
 573        Works like `git push <remote>`, where <remote> is the
 574        current branch's remote (or `origin`, if no remote is
 575        configured for the current branch).
 576
 577`git push origin`::
 578        Without additional configuration, pushes the current branch to
 579        the configured upstream (`remote.origin.merge` configuration
 580        variable) if it has the same name as the current branch, and
 581        errors out without pushing otherwise.
 582+
 583The default behavior of this command when no <refspec> is given can be
 584configured by setting the `push` option of the remote, or the `push.default`
 585configuration variable.
 586+
 587For example, to default to pushing only the current branch to `origin`
 588use `git config remote.origin.push HEAD`.  Any valid <refspec> (like
 589the ones in the examples below) can be configured as the default for
 590`git push origin`.
 591
 592`git push origin :`::
 593        Push "matching" branches to `origin`. See
 594        <refspec> in the <<OPTIONS,OPTIONS>> section above for a
 595        description of "matching" branches.
 596
 597`git push origin master`::
 598        Find a ref that matches `master` in the source repository
 599        (most likely, it would find `refs/heads/master`), and update
 600        the same ref (e.g. `refs/heads/master`) in `origin` repository
 601        with it.  If `master` did not exist remotely, it would be
 602        created.
 603
 604`git push origin HEAD`::
 605        A handy way to push the current branch to the same name on the
 606        remote.
 607
 608`git push mothership master:satellite/master dev:satellite/dev`::
 609        Use the source ref that matches `master` (e.g. `refs/heads/master`)
 610        to update the ref that matches `satellite/master` (most probably
 611        `refs/remotes/satellite/master`) in the `mothership` repository;
 612        do the same for `dev` and `satellite/dev`.
 613+
 614See the section describing `<refspec>...` above for a discussion of
 615the matching semantics.
 616+
 617This is to emulate `git fetch` run on the `mothership` using `git
 618push` that is run in the opposite direction in order to integrate
 619the work done on `satellite`, and is often necessary when you can
 620only make connection in one way (i.e. satellite can ssh into
 621mothership but mothership cannot initiate connection to satellite
 622because the latter is behind a firewall or does not run sshd).
 623+
 624After running this `git push` on the `satellite` machine, you would
 625ssh into the `mothership` and run `git merge` there to complete the
 626emulation of `git pull` that were run on `mothership` to pull changes
 627made on `satellite`.
 628
 629`git push origin HEAD:master`::
 630        Push the current branch to the remote ref matching `master` in the
 631        `origin` repository. This form is convenient to push the current
 632        branch without thinking about its local name.
 633
 634`git push origin master:refs/heads/experimental`::
 635        Create the branch `experimental` in the `origin` repository
 636        by copying the current `master` branch.  This form is only
 637        needed to create a new branch or tag in the remote repository when
 638        the local name and the remote name are different; otherwise,
 639        the ref name on its own will work.
 640
 641`git push origin :experimental`::
 642        Find a ref that matches `experimental` in the `origin` repository
 643        (e.g. `refs/heads/experimental`), and delete it.
 644
 645`git push origin +dev:master`::
 646        Update the origin repository's master branch with the dev branch,
 647        allowing non-fast-forward updates.  *This can leave unreferenced
 648        commits dangling in the origin repository.*  Consider the
 649        following situation, where a fast-forward is not possible:
 650+
 651----
 652            o---o---o---A---B  origin/master
 653                     \
 654                      X---Y---Z  dev
 655----
 656+
 657The above command would change the origin repository to
 658+
 659----
 660                      A---B  (unnamed branch)
 661                     /
 662            o---o---o---X---Y---Z  master
 663----
 664+
 665Commits A and B would no longer belong to a branch with a symbolic name,
 666and so would be unreachable.  As such, these commits would be removed by
 667a `git gc` command on the origin repository.
 668
 669include::transfer-data-leaks.txt[]
 670
 671GIT
 672---
 673Part of the linkgit:git[1] suite