# How to git diff for MS-Excel files(xls/xlsx) on Mac-OS

## Installation

### Prerequisites

* Requires Java 1.6 or higher.
* Assumes Java is added to PATH (to check open a cmd and run java -version)
* No other platform specific requirements
* A shell script and a bat script are packaged

Just [download](https://github.com/na-ka-na/ExcelCompare/releases) the zip file.

Extract it anywhere (and optionally you add the bin folder to PATH).

#### macOS

[Homebrew](http://brew.sh/) makes it easy to install ExcelCompare:

    $ brew update
    $ brew install excel-compare
## All what you have yo do
1. Create **exceldiff.cmd** command file anywhere with write permission and add the following to it:<br/>
    _\<path-to-the-excel-compare-installation-folder\>/bin/excel_cmp $2 $5_<br/>
    e.g.  
        _/usr/local/Cellar/excel-compare/0.6.1/bin/excel_cmp $2 $5_
    
    Why arguments **two** and **five**? It’s because Git passes seven arguments to a diff command, of which the second is the path to the old file (which likely is a temporary file) and the fifth is the path to the new file. For more detailed information, have a look at the [Git documentation](https://git-scm.com/book/en/v2/Customizing-Git-Git-Attributes), specifically under GIT_EXTERNAL_DIFF.

2. Edit the **.git/config** file in your repository and amend the following path:<br/>
    _[diff "excel"]<br/>
            command = \<path-of-the-command-file-above\>_<br/>
    e.g.     
    _[diff "excel"]<br/>
            command = /usr/local/Cellar/excel-compare/0.6.1/bin/exceldiff.cmd_
        
3. Next, we must tell Git to associate certain files with the excel diff driver. To do so, edit **.gitattributes** in the root of your repository and amend the following:<br/>
    _*.xlsx diff=excel_ <br/>
    _*.xls diff=excel_
    
 **Note:**
 * Git attributes are set either in a **.gitattributes** file in one of your directories (normally the root of your project) or in the .**git/info/attributes** file if you don’t want the attributes file committed with your project. 
 * **.gitattributes** (unlike **.gitignore**) must be committed to have any effect, so add it to a commit at this point.

## Usage
* Compare with HEAD revision<br/>
    **_git diff \<file_name\>_**
* Compare file between 2 commits<br/>
    **_git diff \<left_commit_id\> \<right_commit_id\> \<file_name\>_**