git-merge - Join two or more development histories together


   git merge [-n] [--stat] [--no-commit] [--squash] [--[no-]edit]
           [-s <strategy>] [-X <strategy-option>] [-S[<keyid>]]
           [--[no-]rerere-autoupdate] [-m <msg>] [<commit>...]
   git merge <msg> HEAD <commit>...
   git merge --abort


   Incorporates changes from the named commits (since the time their
   histories diverged from the current branch) into the current branch.
   This command is used by git pull to incorporate changes from another
   repository and can be used by hand to merge changes from one branch
   into another.

   Assume the following history exists and the current branch is "master":

                 A---B---C topic
           D---E---F---G master

   Then "git merge topic" will replay the changes made on the topic branch
   since it diverged from master (i.e., E) until its current commit (C) on
   top of master, and record the result in a new commit along with the
   names of the two parent commits and a log message from the user
   describing the changes.

                 A---B---C topic
                /         \
           D---E---F---G---H master

   The second syntax (<msg> HEAD <commit>...) is supported for historical
   reasons. Do not use it from the command line or in new scripts. It is
   the same as git merge -m <msg> <commit>....

   The third syntax ("git merge --abort") can only be run after the merge
   has resulted in conflicts. git merge --abort will abort the merge
   process and try to reconstruct the pre-merge state. However, if there
   were uncommitted changes when the merge started (and especially if
   those changes were further modified after the merge was started), git
   merge --abort will in some cases be unable to reconstruct the original
   (pre-merge) changes. Therefore:

   Warning: Running git merge with non-trivial uncommitted changes is
   discouraged: while possible, it may leave you in a state that is hard
   to back out of in the case of a conflict.


   --commit, --no-commit
       Perform the merge and commit the result. This option can be used to
       override --no-commit.

       With --no-commit perform the merge but pretend the merge failed and
       do not autocommit, to give the user a chance to inspect and further
       tweak the merge result before committing.

   --edit, -e, --no-edit
       Invoke an editor before committing successful mechanical merge to
       further edit the auto-generated merge message, so that the user can
       explain and justify the merge. The --no-edit option can be used to
       accept the auto-generated message (this is generally discouraged).
       The --edit (or -e) option is still useful if you are giving a draft
       message with the -m option from the command line and want to edit
       it in the editor.

       Older scripts may depend on the historical behaviour of not
       allowing the user to edit the merge log message. They will see an
       editor opened when they run git merge. To make it easier to adjust
       such scripts to the updated behaviour, the environment variable
       GIT_MERGE_AUTOEDIT can be set to no at the beginning of them.

       When the merge resolves as a fast-forward, only update the branch
       pointer, without creating a merge commit. This is the default

       Create a merge commit even when the merge resolves as a
       fast-forward. This is the default behaviour when merging an
       annotated (and possibly signed) tag.

       Refuse to merge and exit with a non-zero status unless the current
       HEAD is already up-to-date or the merge can be resolved as a

   --log[=<n>], --no-log
       In addition to branch names, populate the log message with one-line
       descriptions from at most <n> actual commits that are being merged.
       See also git-fmt-merge-msg(1).

       With --no-log do not list one-line descriptions from the actual
       commits being merged.

   --stat, -n, --no-stat
       Show a diffstat at the end of the merge. The diffstat is also
       controlled by the configuration option merge.stat.

       With -n or --no-stat do not show a diffstat at the end of the

   --squash, --no-squash
       Produce the working tree and index state as if a real merge
       happened (except for the merge information), but do not actually
       make a commit, move the HEAD, or record $GIT_DIR/MERGE_HEAD (to
       cause the next git commit command to create a merge commit). This
       allows you to create a single commit on top of the current branch
       whose effect is the same as merging another branch (or more in case
       of an octopus).

       With --no-squash perform the merge and commit the result. This
       option can be used to override --squash.

   -s <strategy>, --strategy=<strategy>
       Use the given merge strategy; can be supplied more than once to
       specify them in the order they should be tried. If there is no -s
       option, a built-in list of strategies is used instead (git
       merge-recursive when merging a single head, git merge-octopus

   -X <option>, --strategy-option=<option>
       Pass merge strategy specific option through to the merge strategy.

   --verify-signatures, --no-verify-signatures
       Verify that the tip commit of the side branch being merged is
       signed with a valid key, i.e. a key that has a valid uid: in the
       default trust model, this means the signing key has been signed by
       a trusted key. If the tip commit of the side branch is not signed
       with a valid key, the merge is aborted.

   --summary, --no-summary
       Synonyms to --stat and --no-stat; these are deprecated and will be
       removed in the future.

   -q, --quiet
       Operate quietly. Implies --no-progress.

   -v, --verbose
       Be verbose.

   --progress, --no-progress
       Turn progress on/off explicitly. If neither is specified, progress
       is shown if standard error is connected to a terminal. Note that
       not all merge strategies may support progress reporting.

       By default, git merge command refuses to merge histories that do
       not share a common ancestor. This option can be used to override
       this safety when merging histories of two projects that started
       their lives independently. As that is a very rare occasion, no
       configuration variable to enable this by default exists and will
       not be added.

   -S[<keyid>], --gpg-sign[=<keyid>]
       GPG-sign the resulting merge commit. The keyid argument is optional
       and defaults to the committer identity; if specified, it must be
       stuck to the option without a space.

   -m <msg>
       Set the commit message to be used for the merge commit (in case one
       is created).

       If --log is specified, a shortlog of the commits being merged will
       be appended to the specified message.

       The git fmt-merge-msg command can be used to give a good default
       for automated git merge invocations. The automated message can
       include the branch description.

       Allow the rerere mechanism to update the index with the result of
       auto-conflict resolution if possible.

       Abort the current conflict resolution process, and try to
       reconstruct the pre-merge state.

       If there were uncommitted worktree changes present when the merge
       started, git merge --abort will in some cases be unable to
       reconstruct these changes. It is therefore recommended to always
       commit or stash your changes before running git merge.

       git merge --abort is equivalent to git reset --merge when
       MERGE_HEAD is present.

       Commits, usually other branch heads, to merge into our branch.
       Specifying more than one commit will create a merge with more than
       two parents (affectionately called an Octopus merge).

       If no commit is given from the command line, merge the
       remote-tracking branches that the current branch is configured to
       use as its upstream. See also the configuration section of this
       manual page.

       When FETCH_HEAD (and no other commit) is specified, the branches
       recorded in the .git/FETCH_HEAD file by the previous invocation of
       git fetch for merging are merged to the current branch.


   Before applying outside changes, you should get your own work in good
   shape and committed locally, so it will not be clobbered if there are
   conflicts. See also git-stash(1). git pull and git merge will stop
   without doing anything when local uncommitted changes overlap with
   files that git pull/git merge may need to update.

   To avoid recording unrelated changes in the merge commit, git pull and
   git merge will also abort if there are any changes registered in the
   index relative to the HEAD commit. (One exception is when the changed
   index entries are in the state that would result from the merge

   If all named commits are already ancestors of HEAD, git merge will exit
   early with the message "Already up-to-date."


   Often the current branch head is an ancestor of the named commit. This
   is the most common case especially when invoked from git pull: you are
   tracking an upstream repository, you have committed no local changes,
   and now you want to update to a newer upstream revision. In this case,
   a new commit is not needed to store the combined history; instead, the
   HEAD (along with the index) is updated to point at the named commit,
   without creating an extra merge commit.

   This behavior can be suppressed with the --no-ff option.


   Except in a fast-forward merge (see above), the branches to be merged
   must be tied together by a merge commit that has both of them as its

   A merged version reconciling the changes from all branches to be merged
   is committed, and your HEAD, index, and working tree are updated to it.
   It is possible to have modifications in the working tree as long as
   they do not overlap; the update will preserve them.

   When it is not obvious how to reconcile the changes, the following

    1. The HEAD pointer stays the same.

    2. The MERGE_HEAD ref is set to point to the other branch head.

    3. Paths that merged cleanly are updated both in the index file and in
       your working tree.

    4. For conflicting paths, the index file records up to three versions:
       stage 1 stores the version from the common ancestor, stage 2 from
       HEAD, and stage 3 from MERGE_HEAD (you can inspect the stages with
       git ls-files -u). The working tree files contain the result of the
       "merge" program; i.e. 3-way merge results with familiar conflict
       markers <<< === >>>.

    5. No other changes are made. In particular, the local modifications
       you had before you started merge will stay the same and the index
       entries for them stay as they were, i.e. matching HEAD.

   If you tried a merge which resulted in complex conflicts and want to
   start over, you can recover with git merge --abort.


   When merging an annotated (and possibly signed) tag, Git always creates
   a merge commit even if a fast-forward merge is possible, and the commit
   message template is prepared with the tag message. Additionally, if the
   tag is signed, the signature check is reported as a comment in the
   message template. See also git-tag(1).

   When you want to just integrate with the work leading to the commit
   that happens to be tagged, e.g. synchronizing with an upstream release
   point, you may not want to make an unnecessary merge commit.

   In such a case, you can "unwrap" the tag yourself before feeding it to
   git merge, or pass --ff-only when you do not have any work on your own.

       git fetch origin
       git merge v1.2.3^0
       git merge --ff-only v1.2.3


   During a merge, the working tree files are updated to reflect the
   result of the merge. Among the changes made to the common ancestor's
   version, non-overlapping ones (that is, you changed an area of the file
   while the other side left that area intact, or vice versa) are
   incorporated in the final result verbatim. When both sides made changes
   to the same area, however, Git cannot randomly pick one side over the
   other, and asks you to resolve it by leaving what both sides did to
   that area.

   By default, Git uses the same style as the one used by the "merge"
   program from the RCS suite to present such a conflicted hunk, like

       Here are lines that are either unchanged from the common
       ancestor, or cleanly resolved because only one side changed.
       <<<<<<< yours:sample.txt
       Conflict resolution is hard;
       let's go shopping.
       Git makes conflict resolution easy.
       >>>>>>> theirs:sample.txt
       And here is another line that is cleanly resolved or unmodified.

   The area where a pair of conflicting changes happened is marked with
   markers <<<<<<<, =======, and >>>>>>>. The part before the ======= is
   typically your side, and the part afterwards is typically their side.

   The default format does not show what the original said in the
   conflicting area. You cannot tell how many lines are deleted and
   replaced with Barbie's remark on your side. The only thing you can tell
   is that your side wants to say it is hard and you'd prefer to go
   shopping, while the other side wants to claim it is easy.

   An alternative style can be used by setting the "merge.conflictStyle"
   configuration variable to "diff3". In "diff3" style, the above conflict
   may look like this:

       Here are lines that are either unchanged from the common
       ancestor, or cleanly resolved because only one side changed.
       <<<<<<< yours:sample.txt
       Conflict resolution is hard;
       let's go shopping.
       Conflict resolution is hard.
       Git makes conflict resolution easy.
       >>>>>>> theirs:sample.txt
       And here is another line that is cleanly resolved or unmodified.

   In addition to the <<<<<<<, =======, and >>>>>>> markers, it uses
   another ||||||| marker that is followed by the original text. You can
   tell that the original just stated a fact, and your side simply gave in
   to that statement and gave up, while the other side tried to have a
   more positive attitude. You can sometimes come up with a better
   resolution by viewing the original.


   After seeing a conflict, you can do two things:

   *   Decide not to merge. The only clean-ups you need are to reset the
       index file to the HEAD commit to reverse 2. and to clean up working
       tree changes made by 2. and 3.; git merge --abort can be used for

   *   Resolve the conflicts. Git will mark the conflicts in the working
       tree. Edit the files into shape and git add them to the index. Use
       git commit to seal the deal.

   You can work through the conflict with a number of tools:

   *   Use a mergetool.  git mergetool to launch a graphical mergetool
       which will work you through the merge.

   *   Look at the diffs.  git diff will show a three-way diff,
       highlighting changes from both the HEAD and MERGE_HEAD versions.

   *   Look at the diffs from each branch.  git log --merge -p <path> will
       show diffs first for the HEAD version and then the MERGE_HEAD

   *   Look at the originals.  git show :1:filename shows the common
       ancestor, git show :2:filename shows the HEAD version, and git show
       :3:filename shows the MERGE_HEAD version.


   *   Merge branches fixes and enhancements on top of the current branch,
       making an octopus merge:

           $ git merge fixes enhancements

   *   Merge branch obsolete into the current branch, using ours merge

           $ git merge -s ours obsolete

   *   Merge branch maint into the current branch, but do not make a new
       commit automatically:

           $ git merge --no-commit maint

       This can be used when you want to include further changes to the
       merge, or want to write your own merge commit message.

       You should refrain from abusing this option to sneak substantial
       changes into a merge commit. Small fixups like bumping
       release/version name would be acceptable.


   The merge mechanism (git merge and git pull commands) allows the
   backend merge strategies to be chosen with -s option. Some strategies
   can also take their own options, which can be passed by giving
   -X<option> arguments to git merge and/or git pull.

       This can only resolve two heads (i.e. the current branch and
       another branch you pulled from) using a 3-way merge algorithm. It
       tries to carefully detect criss-cross merge ambiguities and is
       considered generally safe and fast.

       This can only resolve two heads using a 3-way merge algorithm. When
       there is more than one common ancestor that can be used for 3-way
       merge, it creates a merged tree of the common ancestors and uses
       that as the reference tree for the 3-way merge. This has been
       reported to result in fewer merge conflicts without causing
       mismerges by tests done on actual merge commits taken from Linux
       2.6 kernel development history. Additionally this can detect and
       handle merges involving renames. This is the default merge strategy
       when pulling or merging one branch.

       The recursive strategy can take the following options:

           This option forces conflicting hunks to be auto-resolved
           cleanly by favoring our version. Changes from the other tree
           that do not conflict with our side are reflected to the merge
           result. For a binary file, the entire contents are taken from
           our side.

           This should not be confused with the ours merge strategy, which
           does not even look at what the other tree contains at all. It
           discards everything the other tree did, declaring our history
           contains all that happened in it.

           This is the opposite of ours.

           With this option, merge-recursive spends a little extra time to
           avoid mismerges that sometimes occur due to unimportant
           matching lines (e.g., braces from distinct functions). Use this
           when the branches to be merged have diverged wildly. See also
           git-diff(1) --patience.

           Tells merge-recursive to use a different diff algorithm, which
           can help avoid mismerges that occur due to unimportant matching
           lines (such as braces from distinct functions). See also git-
           diff(1) --diff-algorithm.

       ignore-space-change, ignore-all-space, ignore-space-at-eol
           Treats lines with the indicated type of whitespace change as
           unchanged for the sake of a three-way merge. Whitespace changes
           mixed with other changes to a line are not ignored. See also
           git-diff(1) -b, -w, and --ignore-space-at-eol.

           *   If their version only introduces whitespace changes to a
               line, our version is used;

           *   If our version introduces whitespace changes but their
               version includes a substantial change, their version is

           *   Otherwise, the merge proceeds in the usual way.

           This runs a virtual check-out and check-in of all three stages
           of a file when resolving a three-way merge. This option is
           meant to be used when merging branches with different clean
           filters or end-of-line normalization rules. See "Merging
           branches with differing checkin/checkout attributes" in
           gitattributes(5) for details.

           Disables the renormalize option. This overrides the
           merge.renormalize configuration variable.

           Turn off rename detection. See also git-diff(1) --no-renames.

           Turn on rename detection, optionally setting the similarity
           threshold. This is the default. See also git-diff(1)

           Deprecated synonym for find-renames=<n>.

           This option is a more advanced form of subtree strategy, where
           the strategy makes a guess on how two trees must be shifted to
           match with each other when merging. Instead, the specified path
           is prefixed (or stripped from the beginning) to make the shape
           of two trees to match.

       This resolves cases with more than two heads, but refuses to do a
       complex merge that needs manual resolution. It is primarily meant
       to be used for bundling topic branch heads together. This is the
       default merge strategy when pulling or merging more than one

       This resolves any number of heads, but the resulting tree of the
       merge is always that of the current branch head, effectively
       ignoring all changes from all other branches. It is meant to be
       used to supersede old development history of side branches. Note
       that this is different from the -Xours option to the recursive
       merge strategy.

       This is a modified recursive strategy. When merging trees A and B,
       if B corresponds to a subtree of A, B is first adjusted to match
       the tree structure of A, instead of reading the trees at the same
       level. This adjustment is also done to the common ancestor tree.

   With the strategies that use 3-way merge (including the default,
   recursive), if a change is made on both branches, but later reverted on
   one of the branches, that change will be present in the merged result;
   some people find this behavior confusing. It occurs because only the
   heads and the merge base are considered when performing a merge, not
   the individual commits. The merge algorithm therefore considers the
   reverted change as no change at all, and substitutes the changed
   version instead.


       Specify the style in which conflicted hunks are written out to
       working tree files upon merge. The default is "merge", which shows
       a <<<<<<< conflict marker, changes made by one side, a =======
       marker, changes made by the other side, and then a >>>>>>> marker.
       An alternate style, "diff3", adds a ||||||| marker and the original
       text before the ======= marker.

       If merge is called without any commit argument, merge the upstream
       branches configured for the current branch by using their last
       observed values stored in their remote-tracking branches. The
       values of the branch.<current branch>.merge that name the branches
       at the remote named by branch.<current branch>.remote are
       consulted, and then they are mapped via remote.<remote>.fetch to
       their corresponding remote-tracking branches, and the tips of these
       tracking branches are merged.

       By default, Git does not create an extra merge commit when merging
       a commit that is a descendant of the current commit. Instead, the
       tip of the current branch is fast-forwarded. When set to false,
       this variable tells Git to create an extra merge commit in such a
       case (equivalent to giving the --no-ff option from the command
       line). When set to only, only such fast-forward merges are allowed
       (equivalent to giving the --ff-only option from the command line).

       In addition to branch names, populate the log message with the
       branch description text associated with them. Defaults to false.

       In addition to branch names, populate the log message with at most
       the specified number of one-line descriptions from the actual
       commits that are being merged. Defaults to false, and true is a
       synonym for 20.

       The number of files to consider when performing rename detection
       during a merge; if not specified, defaults to the value of

       Tell Git that canonical representation of files in the repository
       has changed over time (e.g. earlier commits record text files with
       CRLF line endings, but recent ones use LF line endings). In such a
       repository, Git can convert the data recorded in commits to a
       canonical form before performing a merge to reduce unnecessary
       conflicts. For more information, see section "Merging branches with
       differing checkin/checkout attributes" in gitattributes(5).

       Whether to print the diffstat between ORIG_HEAD and the merge
       result at the end of the merge. True by default.

       Controls which merge tool is used by git-mergetool(1). The list
       below shows the valid built-in values. Any other value is treated
       as a custom merge tool and requires that a corresponding
       mergetool.<tool>.cmd variable is defined.

       *   araxis

       *   bc

       *   bc3

       *   codecompare

       *   deltawalker

       *   diffmerge

       *   diffuse

       *   ecmerge

       *   emerge

       *   examdiff

       *   gvimdiff

       *   gvimdiff2

       *   gvimdiff3

       *   kdiff3

       *   meld

       *   opendiff

       *   p4merge

       *   tkdiff

       *   tortoisemerge

       *   vimdiff

       *   vimdiff2

       *   vimdiff3

       *   winmerge

       *   xxdiff

       Controls the amount of output shown by the recursive merge
       strategy. Level 0 outputs nothing except a final error message if
       conflicts were detected. Level 1 outputs only conflicts, 2 outputs
       conflicts and file changes. Level 5 and above outputs debugging
       information. The default is level 2. Can be overridden by the
       GIT_MERGE_VERBOSITY environment variable.

       Defines a human-readable name for a custom low-level merge driver.
       See gitattributes(5) for details.

       Defines the command that implements a custom low-level merge
       driver. See gitattributes(5) for details.

       Names a low-level merge driver to be used when performing an
       internal merge between common ancestors. See gitattributes(5) for

       Sets default options for merging into branch <name>. The syntax and
       supported options are the same as those of git merge, but option
       values containing whitespace characters are currently not


   git-fmt-merge-msg(1), git-pull(1), gitattributes(5), git-reset(1), git-
   diff(1), git-ls-files(1), git-add(1), git-rm(1), git-mergetool(1)


   Part of the git(1) suite


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