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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.vimdiff.layout
The vimdiff backend uses this variable to control how its split windows appear.
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.
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 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 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
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