git-mergetool(1) — Linux manual page


GIT-MERGETOOL(1)               Git Manual               GIT-MERGETOOL(1)

NAME         top

       git-mergetool - Run merge conflict resolution tools to resolve
       merge conflicts

SYNOPSIS         top

       git mergetool [--tool=<tool>] [-y | --[no-]prompt] [<file>...]

DESCRIPTION         top

       Use git mergetool to run one of several merge utilities to
       resolve merge conflicts. It is typically run after git merge.

       If one or more <file> parameters are given, the merge tool
       program will be run to resolve differences in each file (skipping
       those without conflicts). Specifying a directory will include all
       unresolved files in that path. If no <file> names are specified,
       git mergetool will run the merge tool program on every file with
       merge conflicts.

OPTIONS         top

       -t <tool>, --tool=<tool>
           Use the merge resolution program specified by <tool>. Valid
           values include emerge, gvimdiff, kdiff3, meld, vimdiff, and
           tortoisemerge. Run git mergetool --tool-help for the list of
           valid <tool> settings.

           If a merge resolution program is not specified, git mergetool
           will use the configuration variable merge.tool. If the
           configuration variable merge.tool is not set, git mergetool
           will pick a suitable default.

           You can explicitly provide a full path to the tool by setting
           the configuration variable mergetool.<tool>.path. For
           example, you can configure the absolute path to kdiff3 by
           setting mergetool.kdiff3.path. Otherwise, git mergetool
           assumes the tool is available in PATH.

           Instead of running one of the known merge tool programs, git
           mergetool can be customized to run an alternative program by
           specifying the command line to invoke in a configuration
           variable mergetool.<tool>.cmd.

           When git mergetool is invoked with this tool (either through
           the -t or --tool option or the merge.tool configuration
           variable), the configured command line will be invoked with
           $BASE set to the name of a temporary file containing the
           common base for the merge, if available; $LOCAL set to the
           name of a temporary file containing the contents of the file
           on the current branch; $REMOTE set to the name of a temporary
           file containing the contents of the file to be merged, and
           $MERGED set to the name of the file to which the merge tool
           should write the result of the merge resolution.

           If the custom merge tool correctly indicates the success of a
           merge resolution with its exit code, then the configuration
           variable mergetool.<tool>.trustExitCode can be set to true.
           Otherwise, git mergetool will prompt the user to indicate the
           success of the resolution after the custom tool has exited.

           Print a list of merge tools that may be used with --tool.

       -y, --no-prompt
           Don’t prompt before each invocation of the merge resolution
           program. This is the default if the merge resolution program
           is explicitly specified with the --tool option or with the
           merge.tool configuration variable.

           Prompt before each invocation of the merge resolution program
           to give the user a chance to skip the path.

       -g, --gui
           When git-mergetool is invoked with the -g or --gui option,
           the default merge tool will be read from the configured
           merge.guitool variable instead of merge.tool. If
           merge.guitool is not set, we will fallback to the tool
           configured under merge.tool. This may be autoselected using
           the configuration variable mergetool.guiDefault.

           This overrides a previous -g or --gui setting or
           mergetool.guiDefault configuration and reads the default
           merge tool from the configured merge.tool variable.

           Process files in the order specified in the <orderfile>,
           which has one shell glob pattern per line. This overrides the
           diff.orderFile configuration variable (see git-config(1)). To
           cancel diff.orderFile, use -O/dev/null.


       Everything below this line in this section is selectively
       included from the git-config(1) documentation. The content is the
       same as what’s found there:

           Override the path for the given tool. This is useful in case
           your tool is not in the PATH.

           Specify the command to invoke the specified merge tool. The
           specified command is evaluated in shell with the following
           variables available: BASE is the name of a temporary file
           containing the common base of the files to be merged, if
           available; LOCAL is the name of a temporary file containing
           the contents of the file on the current branch; REMOTE is the
           name of a temporary file containing the contents of the file
           from the branch being merged; MERGED contains the name of the
           file to which the merge tool should write the results of a
           successful merge.

           Allows the user to override the global mergetool.hideResolved
           value for a specific tool. See mergetool.hideResolved for the
           full description.

           For a custom merge command, specify whether the exit code of
           the merge command can be used to determine whether the merge
           was successful. If this is not set to true then the merge
           target file timestamp is checked, and the merge is assumed to
           have been successful if the file has been updated; otherwise,
           the user is prompted to indicate the success of the merge.

           Older versions of meld do not support the --output option.
           Git will attempt to detect whether meld supports --output by
           inspecting the output of meld --help. Configuring
           mergetool.meld.hasOutput will make Git skip these checks and
           use the configured value instead. Setting
           mergetool.meld.hasOutput to true tells Git to unconditionally
           use the --output option, and false avoids using --output.

           When the --auto-merge is given, meld will merge all
           non-conflicting parts automatically, highlight the
           conflicting parts, and wait for user decision. Setting
           mergetool.meld.useAutoMerge to true tells Git to
           unconditionally use the --auto-merge option with meld.
           Setting this value to auto makes git detect whether
           --auto-merge is supported and will only use --auto-merge when
           available. A value of false avoids using --auto-merge
           altogether, and is the default value.

       mergetool.<vimdiff variant>.layout
           Configure the split window layout for vimdiff’s <variant>,
           which is any of vimdiff, nvimdiff, gvimdiff. Upon launching
           git mergetool with --tool=<variant> (or without --tool if
           merge.tool is configured as <variant>), Git will consult
           mergetool.<variant>.layout to determine the tool’s layout. If
           the variant-specific configuration is not available,
           vimdiff's is used as fallback. If that too is not available,
           a default layout with 4 windows will be used. To configure
           the layout, see the BACKEND SPECIFIC HINTS section.

           During a merge, Git will automatically resolve as many
           conflicts as possible and write the MERGED file containing
           conflict markers around any conflicts that it cannot resolve;
           LOCAL and REMOTE normally represent the versions of the file
           from before Git’s conflict resolution. This flag causes LOCAL
           and REMOTE to be overwritten so that only the unresolved
           conflicts are presented to the merge tool. Can be configured
           per-tool via the mergetool.<tool>.hideResolved configuration
           variable. Defaults to false.

           After performing a merge, the original file with conflict
           markers can be saved as a file with a .orig extension. If
           this variable is set to false then this file is not
           preserved. Defaults to true (i.e. keep the backup files).

           When invoking a custom merge tool, Git uses a set of
           temporary files to pass to the tool. If the tool returns an
           error and this variable is set to true, then these temporary
           files will be preserved; otherwise, they will be removed
           after the tool has exited. Defaults to false.

           Git writes temporary BASE, LOCAL, and REMOTE versions of
           conflicting files in the worktree by default. Git will
           attempt to use a temporary directory for these files when set
           true. Defaults to false.

           Prompt before each invocation of the merge resolution

           Set true to use the merge.guitool by default (equivalent to
           specifying the --gui argument), or auto to select
           merge.guitool or merge.tool depending on the presence of a
           DISPLAY environment variable value. The default is false,
           where the --gui argument must be provided explicitly for the
           merge.guitool to be used.


       git mergetool creates *.orig backup files while resolving merges.
       These are safe to remove once a file has been merged and its git
       mergetool session has completed.

       Setting the mergetool.keepBackup configuration variable to false
       causes git mergetool to automatically remove the backup files as
       files are successfully merged.



           When specifying --tool=vimdiff in git mergetool Git will open
           Vim with a 4 windows layout distributed in the following way:

               |             |           |              |
               |   LOCAL     |   BASE    |   REMOTE     |
               |             |           |              |
               |                                        |
               |                MERGED                  |
               |                                        |

           LOCAL, BASE and REMOTE are read-only buffers showing the
           contents of the conflicting file in specific commits ("commit
           you are merging into", "common ancestor commit" and "commit
           you are merging from" respectively)

           MERGED is a writable buffer where you have to resolve the
           conflicts (using the other read-only buffers as a reference).
           Once you are done, save and exit Vim as usual (:wq) or, if
           you want to abort, exit using :cq.

       Layout configuration

           You can change the windows layout used by Vim by setting
           configuration variable mergetool.vimdiff.layout which accepts
           a string where the following separators have special meaning:

           •   + is used to "open a new tab"

           •   , is used to "open a new vertical split"

           •   / is used to "open a new horizontal split"

           •   @ is used to indicate the file containing the final
               version after solving the conflicts. If not present,
               MERGED will be used by default.

           The precedence of the operators is as follows (you can use
           parentheses to change it):

               `@` > `+` > `/` > `,`

           Let’s see some examples to understand how it works:

           •   layout = "(LOCAL,BASE,REMOTE)/MERGED"

               This is exactly the same as the default layout we have
               already seen.

               Note that / has precedence over , and thus the
               parenthesis are not needed in this case. The next layout
               definition is equivalent:

                   layout = "LOCAL,BASE,REMOTE / MERGED"

           •   layout = "LOCAL,MERGED,REMOTE"

               If, for some reason, we are not interested in the BASE

                   |             |           |              |
                   |             |           |              |
                   |   LOCAL     |   MERGED  |   REMOTE     |
                   |             |           |              |
                   |             |           |              |

           •   layout = "MERGED"

               Only the MERGED buffer will be shown. Note, however, that
               all the other ones are still loaded in vim, and you can
               access them with the "buffers" command.

                   |                                        |
                   |                                        |
                   |                 MERGED                 |
                   |                                        |
                   |                                        |

           •   layout = "@LOCAL,REMOTE"

               When MERGED is not present in the layout, you must "mark"
               one of the buffers with an asterisk. That will become the
               buffer you need to edit and save after resolving the

                   |                   |                    |
                   |                   |                    |
                   |                   |                    |
                   |     LOCAL         |    REMOTE          |
                   |                   |                    |
                   |                   |                    |
                   |                   |                    |

           •   layout = "LOCAL,BASE,REMOTE / MERGED + BASE,LOCAL +

               Three tabs will open: the first one is a copy of the
               default layout, while the other two only show the
               differences between (BASE and LOCAL) and (BASE and
               REMOTE) respectively.

                   | <TAB #1> |  TAB #2  |  TAB #3  |       |
                   |             |           |              |
                   |   LOCAL     |   BASE    |   REMOTE     |
                   |             |           |              |
                   |                                        |
                   |                MERGED                  |
                   |                                        |

                   |  TAB #1  | <TAB #2> |  TAB #3  |       |
                   |                   |                    |
                   |                   |                    |
                   |                   |                    |
                   |     BASE          |    LOCAL           |
                   |                   |                    |
                   |                   |                    |
                   |                   |                    |

                   |  TAB #1  |  TAB #2  | <TAB #3> |       |
                   |                   |                    |
                   |                   |                    |
                   |                   |                    |
                   |     BASE          |    REMOTE          |
                   |                   |                    |
                   |                   |                    |
                   |                   |                    |

           •   layout = "LOCAL,BASE,REMOTE / MERGED + BASE,LOCAL +

               Same as the previous example, but adds a fourth tab with
               the same information as the first tab, with a different

                   |  TAB #1  |  TAB #2  |  TAB #3  | <TAB #4> |
                   |       LOCAL         |                     |
                   |---------------------|                     |
                   |       BASE          |        MERGED       |
                   |---------------------|                     |
                   |       REMOTE        |                     |

               Note how in the third tab definition we need to use
               parentheses to make , have precedence over /.


           Instead of --tool=vimdiff, you can also use one of these
           other variants:

           •   --tool=gvimdiff, to open gVim instead of Vim.

           •   --tool=nvimdiff, to open Neovim instead of Vim.

           When using these variants, in order to specify a custom
           layout you will have to set configuration variables
           mergetool.gvimdiff.layout and mergetool.nvimdiff.layout
           instead of mergetool.vimdiff.layout (though the latter will
           be used as fallback if the variant-specific one is not set).

           In addition, for backwards compatibility with previous Git
           versions, you can also append 1, 2 or 3 to either vimdiff or
           any of the variants (ex: vimdiff3, nvimdiff1, etc...) to use
           a predefined layout. In other words, using
           --tool=[g,n,]vimdiffx is the same as using
           --tool=[g,n,]vimdiff and setting configuration variable
           mergetool.[g,n,]vimdiff.layout to...

           •   x=1: "@LOCAL, REMOTE"x=2: "LOCAL, MERGED, REMOTE"x=3: "MERGED"

           Example: using --tool=gvimdiff2 will open gvim with three
           columns (LOCAL, MERGED and REMOTE).

GIT         top

       Part of the git(1) suite

COLOPHON         top

       This page is part of the git (Git distributed version control
       system) project.  Information about the project can be found at
       ⟨⟩.  If you have a bug report for this manual
       page, see ⟨⟩.  This page was obtained
       from the project's upstream Git repository
       ⟨⟩ on 2024-06-14.  (At that time,
       the date of the most recent commit that was found in the
       repository was 2024-06-12.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
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       (which is not part of the original manual page), send a mail to

Git         2024-06-12               GIT-MERGETOOL(1)

Pages that refer to this page: git(1)git-config(1)git-difftool(1)git-gui(1)git-merge(1)stg(1)