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

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

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


DESCRIPTION
       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
       -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.

       --tool-help
	   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
	   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.

       --no-gui
	   This overrides a previous -g or --gui setting or
	   mergetool.guiDefault configuration and reads the default merge tool
	   from the configured merge.tool variable.

       -O<orderfile>
	   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.

CONFIGURATION
       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:

       mergetool.<tool>.path
	   Override the path for the given tool. This is useful in case your
	   tool is not in the $PATH.

       mergetool.<tool>.cmd
	   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.

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

       mergetool.<tool>.trustExitCode
	   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.

       mergetool.meld.hasOutput
	   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.

       mergetool.meld.useAutoMerge
	   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.<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.

       mergetool.hideResolved
	   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 are 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.

       mergetool.keepBackup
	   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).

       mergetool.keepTemporaries
	   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.

       mergetool.writeToTemp
	   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.

       mergetool.prompt
	   Prompt before each invocation of the merge resolution program.

       mergetool.guiDefault
	   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.

TEMPORARY FILES
       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.

BACKEND SPECIFIC HINTS
   vimdiff
       Description

	   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 buffer.

		   ------------------------------------------
		   |		 |	     |		    |
		   |		 |	     |		    |
		   |   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 arobase (@). That will become the buffer
	       you need to edit and save after resolving the conflicts.

		   ------------------------------------------
		   |		       |		    |
		   |		       |		    |
		   |		       |		    |
		   |	 LOCAL	       |    REMOTE	    |
		   |		       |		    |
		   |		       |		    |
		   |		       |		    |
		   ------------------------------------------

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

	       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 + BASE,REMOTE
	       + (LOCAL/BASE/REMOTE),MERGED"

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

		   ---------------------------------------------
		   |  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 /.

       Variants

	   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]vimdiff<x> 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
       Part of the git(1) suite

Git 2.51.0			  2025-08-17		      GIT-MERGETOOL(1)