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 on 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.
--no-gui
This overrides a previous -g or --gui setting and reads the default merge tool will be read 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 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.vimdiff.layout
The vimdiff backend uses this variable to control how its split windows look like. Applies even if you are using Neovim
(nvim) or gVim (gvim) as the merge tool. See BACKEND SPECIFIC HINTS section for details.
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 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.
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.
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 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 which is 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 this one (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 asterisk. 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 parenthesis 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
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
Part of the git(1) suite
Git 2.39.2 04/24/2023 GIT-MERGETOOL(1)