Shell script to check git for changes and then loop through changed files?

bash, git, pull, shell

Solution

For your first question, you can use `git diff --quiet` (or `git diff --exit-code`, but generally when you're using it for its exit code you want it not to print output anyhow, and `git diff --quiet` implies `--exit-code`) to determine if there have been any changes. That will give you a 1 value if there are changes, and a 0 if there are not. So if you want to have code that will run only if there are changes:

if ! git --git-dir="/dir/.git" diff --quiet
then
    # do stuff...
fi

For your second question, I'd recommend a `while read ...` loop to read lines from `git diff-tree`:

git --git-dir="/dir/.git" diff-tree ORIG_HEAD.. | \
    while read srcmode dstmode srcsha dstsha status srcfile dstfile
    do
        # do something with $srcfile and $dstfile
    done

Note that `$srcmode` will have an extra `:` at the beginning, and `$dstfile` will only have a value if the file was renamed. If you don't want to worry about renames, pass in `--no-renames`, and instead of seeing renames you'll see just the adds and deletes.

Problem

I am trying write a shell script that does the following: - Checks the remote git repository for any changes to pull. - If there are changes in the remote git repository pull those changes. - Loops through the files that are new or have been modified. Through my research I have found some of the necessary commands to do these things but I haven't been able to get them to work together in a shell script. Here is a script with some of the commands that I have: ``` #!/bin/sh #Check if there are any changed files git --git-dir="/dir/.git" fetch origin if git --git-dir="/dir/.git" log HEAD..origin/master --oneline then #Output the modified files from the last pull git --git-dir="/dir/.git" diff --name-status ORIG_HEAD.. fi ``` The things that I have not been able to get working with the commands in this script are: - The if statement to check if there are changes or not always is true. I have tried if statements with other git commands and they also are always true. It seems that git does not work like normal shell commands where you get a 0 or 1 response. How can I get a git command like this or other git commands to return the right responses in an if statement? - How can I assign the variables output from the command to see the changed files to an array so that I can loop through them using a for? If the commands in my script won't really work in this case what is a better way to do this? Edit: Sorry should have been more clear when I loop through the changed files I need to pull the changes from the remote repository before I loop through the files so that when I work with these files I have the latest changes.

Original source