Git on Windows: How do you set up a mergetool?

I’ve tried msysGit and Git on Cygwin. Both work just fine in and of themselves and both run gitk and git-gui perfectly.

Now how the heck do I configure a mergetool? (Vimdiff works on Cygwin, but preferably I would like something a little more user-friendly for some of our Windows-loving coworkers.)

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    To follow-up on Charles Bailey’s answer, here’s my git setup that’s using p4merge (free cross-platform 3way merge tool); tested on msys Git (Windows) install:

    git config --global merge.tool p4merge
    git config --global mergetool.p4merge.cmd 'p4merge.exe \"$BASE\" \"$LOCAL\" \"$REMOTE\" \"$MERGED\"'
    

    or, from a windows cmd.exe shell, the second line becomes :

    git config --global mergetool.p4merge.cmd "p4merge.exe \"$BASE\" \"$LOCAL\" \"$REMOTE\" \"$MERGED\""
    

    The changes (relative to Charles Bailey):

    • added to global git config, i.e. valid for all git projects not just the current one
    • the custom tool config value resides in “mergetool.[tool].cmd”, not “merge.[tool].cmd” (silly me, spent an hour troubleshooting why git kept complaining about non-existing tool)
    • added double quotes for all file names so that files with spaces can still be found by the merge tool (I tested this in msys Git from Powershell)
    • note that by default Perforce will add its installation dir to PATH, thus no need to specify full path to p4merge in the command

    Download: http://www.perforce.com/product/components/perforce-visual-merge-and-diff-tools


    EDIT (Feb 2014)

    As pointed out by @Gregory Pakosz, latest msys git now “natively” supports p4merge (tested on 1.8.5.2.msysgit.0).

    You can display list of supported tools by running:

    git mergetool --tool-help
    

    You should see p4merge in either available or valid list. If not, please update your git.

    If p4merge was listed as available, it is in your PATH and you only have to set merge.tool:

    git config --global merge.tool p4merge
    

    If it was listed as valid, you have to define mergetool.p4merge.path in addition to merge.tool:

    git config --global mergetool.p4merge.path c:/Users/my-login/AppData/Local/Perforce/p4merge.exe
    
    • The above is an example path when p4merge was installed for the current user, not system-wide (does not need admin rights or UAC elevation)
    • Although ~ should expand to current user’s home directory (so in theory the path should be ~/AppData/Local/Perforce/p4merge.exe), this did not work for me
    • Even better would have been to take advantage of an environment variable (e.g. $LOCALAPPDATA/Perforce/p4merge.exe), git does not seem to be expanding environment variables for paths (if you know how to get this working, please let me know or update this answer)

    setting mergetool.p4merge.cmd will not work anymore since Git has started trying to support p4merge, see libexec/git-core/git-mergetool–lib.so we just need to specify the mergetool path for git,for example the p4merge:

    git config --global mergetool.p4merge.path 'C:\Program Files\Perforce\p4merge.exe'
    git config --global merge.tool p4merge
    

    Then it will work.

    I’m using Portable Git on WinXP (works a treat!), and needed to resolve a conflict that came up in branching. Of all the gui’s I checked, KDiff3 proved to be the most transparent to use.

    But I found the instructions I needed to get it working in Windows in this blog post, instructions which differ slightly from the other approaches listed here. It basically amounted to adding these lines to my .gitconfig file:

    [merge]
        tool = kdiff3
    
    [mergetool "kdiff3"]
        path = C:/YourPathToBinaryHere/KDiff3/kdiff3.exe
        keepBackup = false
        trustExitCode = false
    

    Working nicely now!

    Under Cygwin, the only thing that worked for me is the following:

    git config --global merge.tool myp4merge
    git config --global mergetool.myp4merge.cmd 'p4merge.exe "$(cygpath -wla $BASE)" "$(cygpath -wla $LOCAL)" "$(cygpath -wla $REMOTE)" "$(cygpath -wla $MERGED)"'
    git config --global diff.tool myp4diff
    git config --global difftool.myp4diff.cmd 'p4merge.exe "$(cygpath -wla $LOCAL)" "$(cygpath -wla $REMOTE)"'
    

    Also, I like to turn off the prompt message for difftool:

    git config --global difftool.prompt false
    

    git mergetool is fully configurable so you can pretty much chose your favourite tool.

    The full documentation is here: http://www.kernel.org/pub/software/scm/git/docs/git-mergetool.html

    In brief, you can set a default mergetool by setting the user config variable merge.tool.

    If the merge tool is one of the ones supported natively by it you just have to set mergetool.<tool>.path to the full path to the tool (replace <tool> by what you have configured merge.tool to be.

    Otherwise, you can set mergetool.<tool>.cmd to a bit of shell to be eval’ed at runtime with the shell variables $BASE, $LOCAL, $REMOTE, $MERGED set to the appropriate files. You have to be a bit careful with the escaping whether you directly edit a config file or set the variable with the git config command.

    Something like this should give the flavour of what you can do (‘mymerge’ is a fictional tool).

    git config merge.tool mymerge
    git config merge.mymerge.cmd 'mymerge.exe --base "$BASE" "$LOCAL" "$REMOTE" -o "$MERGED"'
    

    Once you’ve setup your favourite merge tool, it’s simply a matter of running git mergetool whenever you have conflicts to resolve.

    The p4merge tool from Perforce is a pretty good standalone merge tool.

    It seems that newer git versions support p4merge directly, so

    git config --global merge.tool p4merge
    

    should be all you need, if p4merge.exe is on your path. No need to set up cmd or path.

    As already answered here (and here and here), mergetool is the command to configure this. For a nice graphical frontend I recommend kdiff3 (GPL).

    For beyond compare on Windows 7

    git config --global merge.tool bc3
    git config --global mergetool.bc3.path "C:\Program Files (x86)\Beyond Compare 3\BCompare.exe"
    

    I had to drop the extra quoting using msysGit on windows 7, not sure why.

    git config --global merge.tool p4merge
    git config --global mergetool.p4merge.cmd 'p4merge $BASE $LOCAL $REMOTE $MERGED'
    

    If you’re doing this through cygwin, you may need to use cygpath:

    git config --global merge.tool p4merge
    git config --global mergetool.p4merge.cmd 'p4merge `cygpath -w $BASE` `cygpath -w $LOCAL` `cygpath -w $REMOTE` `cygpath -w $MERGED`'
    

    Bah, this finally worked for me (Windows 7 + Cygwin + TortoiseMerge):

    In .git/config:

    cmd = TortoiseMerge.exe /base:$(cygpath -d \"$BASE\") /theirs:$(cygpath -d \"$REMOTE\") /mine:$(cygpath -d \"$LOCAL\") /merged:$(cygpath -d \"$MERGED\")
    

    Thanks to previous posters for the tip to use cygpath!

    i use an app called WinMerge ( http://winmerge.org/ )
    info from their manual ( http://manual.winmerge.org/CommandLine.html )

    this is the bash script i use from the mergetool directive via .gitconfig

    #!/bin/sh
    # using winmerge with git
    # replaces unix style null files with a newly created empty windows temp file
    
    file1=$1
    if [ "$file1" == '/dev/null' ] || [ "$file1" == '\\.\nul' ] || [ ! -e "$file1" ]
        then 
           file1="/tmp/gitnull"
           `echo "">$file1`
    fi
    file2=$2
    if [ "$file2" == '/dev/null' ] || [ "$file2" == '\\.\nul' ] || [ ! -e "$file2" ]
        then 
           file2="/tmp/gitnull"
           `echo "">$file2`
    fi
    echo diff : $1 -- $2
    "C:\Program files (x86)\WinMerge\WinMergeU.exe" -e -ub -dl "Base" -dr "Mine" "$file1" "$file2"
    

    basically the bash accounts for when the result of the diff in an empty file and creates a new temp file in the correct location.

    You may want to add these options too:

    git config --global merge.tool p4mergetool
    git config --global mergetool.p4merge.cmd 'p4merge $BASE $LOCAL $REMOTE $MERGED'
    git config --global mergetool.p4mergetool.trustExitCode false
    git config --global mergetool.keepBackup false
    

    Also, I don’t know why but the quoting and slash from Milan Gardian’s answer screwed things up for me.

    If anyone wants to use gvim as their diff tool on TortoiseGit, then this is what you need to enter into the text input for the path to the external diff tool:

    path\to\gvim.exe -f -d -c "wincmd R" -c "wincmd R" -c "wincmd h" -c "wincmd J"
    

    For IntelliJ IDEA (Community Edition) 3-way git mergetool configuration in Windows environment (~/.gitconfig)

    Cygwin

    [mergetool "ideamerge"]
         cmd = C:/Program\\ Files\\ \\(x86\\)/JetBrains/IntelliJ\\ IDEA\\ Community\\ Edition\\ 14.1.3/bin/idea.exe merge `cygpath -wa $LOCAL` `cygpath -wa $REMOTE` `cygpath -wa $BASE` `cygpath -wa $MERGED`
    [merge]
         tool = ideamerge
    

    Msys

    [mergetool "ideamerge"]
    cmd = "/c/Program\\ Files\\ \\(x86\\)/JetBrains/IntelliJ\\ IDEA\\ Community\\ Edition\\ 14.1.3/bin/idea.exe" merge `~/winpath.sh $LOCAL` `~/winpath.sh $REMOTE` `~/winpath.sh $BASE` `~/winpath.sh $MERGED`
    [merge]
     tool = ideamerge
    

    The ~/winpath.sh is to convert paths to Windows on msys and is taken from msys path conversion question on stackoverflow

    #! /bin/sh                                                               
    
    function wpath {                                                         
        if [ -z "$1" ]; then                                                 
            echo "$@"                                                        
        else                                                                 
            if [ -f "$1" ]; then                                             
                local dir=$(dirname "$1")                                    
                local fn=$(basename "$1")                                    
                echo "$(cd "$dir"; echo "$(pwd -W)/$fn")" | sed 's|/|\\|g';  
            else                                                             
                if [ -d "$1" ]; then                                         
                    echo "$(cd "$1"; pwd -W)" | sed 's|/|\\|g';              
                else                                                         
                    echo "$1" | sed 's|^/\(.\)/|\1:\\|g; s|/|\\|g';          
                fi                                                           
            fi                                                               
        fi                                                                   
    }                                                                        
    
    wpath "$@" 
    

    To setup p4merge, installed using chocolatey on windows for both merge and diff, take a look here:
    https://gist.github.com/CamW/88e95ea8d9f0786d746a

    If you’re having problems opening p4merge from SourceTree look for you local configuration file named config under MyRepo.git and delete any merge configuration.
    In my case it was trying to open Meld which I just uninstalled

    I found two ways to configure “SourceGear DiffMerge” as difftool and mergetool in github Windows.

    The following commands in a Command Prompt window will update your .gitconfig to configure GIT use DiffMerge:

    git config --global diff.tool diffmerge
    git config --global difftool.diffmerge.cmd 'C:/Program\ Files/SourceGear/Common/DiffMerge/sgdm.exe  \"$LOCAL\" \"$REMOTE\"'
    
    git config --global merge.tool diffmerge
    git config --global mergetool.diffmerge.cmd  'C:/Program\ Files/SourceGear/Common/DiffMerge/sgdm.exe  -merge  -result=\"$MERGED\" \"$LOCAL\" \"$BASE\" \"$REMOTE\"'
    

    [OR]

    Add the following lines to your .gitconfig. This file should be in your home directory in C:\Users\UserName:

    [diff]
        tool = diffmerge
    [difftool "diffmerge"]
        cmd = C:/Program\\ Files/SourceGear/Common/DiffMerge/sgdm.exe \"$LOCAL\" \"$REMOTE\"
    
    [merge]
        tool = diffmerge
    [mergetool "diffmerge"]
        trustExitCode = true
        cmd = C:/Program\\ Files/SourceGear/Common/DiffMerge/sgdm.exe -merge -result=\"$MERGED\" \"$LOCAL\" \"$BASE\" \"$REMOTE\"
    
    Git Baby is a git and github fan, let's start git clone.