How can I perform a git diff using a wildcard search?

Question

When I do a git status, I get something like this:

modified   a/mega/super/duper/long/path/to/the/file/foo.php
modified   a/mega/super/duper/long/path/to/the/file/another/folder/bar.php
modified   a/mega/super/duper/long/path/to/the/file/someotherfolder/blahblah.php

If I want to see what has changes for the bar.php-file (line 2) how do I do that?

I was hoping to be able to do something like this:

git diff */bar.php
git diff bar.php

And that git could tab-complete or read my mind. :-)

---

Idea 1: Writing it out:

It's quite extensive having to write:

git diff a/mega/super/duper/long/path/to/the/file/another/folder/bar.php

Idea 2: Use the mouse + Copy/paste

I could use the mouse and copy-paste, but that too seems like a poor solution. Taking the fingers away from the keyboard usually isn't the solution. And I have to do it quite a lot.

Idea 3: Git add patch

By running git add -p, I automatically goes into an interactive mode, being able to do a bunch of stuff. But it's not quite what I'm after.

Idea 4: Using sed

I found this SO-question: git diff just the first file, which suggests this:

git diff $(git diff --name-only | sed -n '1 p')

I could then setup an Alfred-snippet or a bash-script that prints that. Whereafter I can change the 1 to the number of file I would like to see.

This is close to being good.

Idea 5: Bash-script to copy file-name of nth file to clipboard

Another way would be to make a bashscript, that copies the nth-file to the clipboard. Then I could do it in two swift commands, like this:

./copy-file-name-for-first-file-in-git-status.sh     # Named to make easy to understand.
git diff [PASTE]

This would actually also solve it for the bonus-question below.

---

Bonus question - Same problem for git add and git log

The same issue is present, if I don't want to do a git add ., but want to add files individually in the deep nested folders. Then I also have to type my way through the entire path, for every single file.

Answer 1

For ease of use, how about a Git alias rather than an external function? You can put it in your global config and you won't have to mess with remembering the new function or adding it to the path.

As you can see below it will run the diff with only a (potentially) very short substring to identify the file. It's a regex search and will gracefully handle cases when you specify a regex that matches no files or more than one file.

Add this to your git config:

[alias]
        diffr = "!a() { myfile=$(git status | awk '/modified:/ {print $2}' |grep "$1") ; cnt=$(git status |awk '/modified:/ {print $2}'|grep "$1" |wc -l) ;if [ $cnt -eq 1 ] ; then git diff $myfile;else printf '%s Matched %s files\n' $1 $cnt;fi; if ! [ $cnt -eq 0 ] ; then git status |grep "$1"; fi; }; a"

Run it with git diffr "<regex>"

Here's the status of the test repo:

me@mypc MINGW64 /c/repos/aliastest (master)
$ git status
On branch master
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git restore <file>..." to discard changes in working directory)
        modified:   mega/super/duper/long/path/to/the/file/another/folder/bar.php
        modified:   mega/super/duper/long/path/to/the/file/foo.php
        modified:   mega/super/duper/long/path/to/the/file/someotherfolder/blahblah.php

no changes added to commit (use "git add" and/or "git commit -a")

Here's a successful diff for a file with 'foo' in the name (when it's the only matching file):

me@mypc MINGW64 /c/repos/aliastest (master)
$ git diffr foo
warning: LF will be replaced by CRLF in mega/super/duper/long/path/to/the/file/foo.php.
The file will have its original line endings in your working directory
diff --git a/mega/super/duper/long/path/to/the/file/foo.php b/mega/super/duper/long/path/to/the/file/foo.php
index 90be1f3..294186e 100644
--- a/mega/super/duper/long/path/to/the/file/foo.php
+++ b/mega/super/duper/long/path/to/the/file/foo.php
@@ -1 +1 @@
-before
+after

This is how it handles the invalid case where the regex matched more than one file:

me@mypc MINGW64 /c/repos/aliastest (master)
$ git diffr "folder/b[al]"
folder/b[al] Matched 2 files
        modified:   mega/super/duper/long/path/to/the/file/another/folder/bar.php
        modified:   mega/super/duper/long/path/to/the/file/someotherfolder/blahblah.php

Here it is handling a regex that matched no files:

me@mypc MINGW64 /c/repos/aliastest (master)
$ git diffr "sirnotappearinginthisfilm"
sirnotappearinginthisfilm Matched 0 files

Aside from all the escaping it's just a plain Bash function so you can edit it as you please. You could call a separate executable in place of the Bash function but then you'd have external dependencies. Minor adjustments to the script could fulfill your git add request as well. If I find time to write it I'll post it here. Similar functionality with git log seems like a different animal entirely since your possible results can be enormous.

I have had the same desire to keep my hands on the keyboard and the same problems with Git on the command line, but until now I hadn't really thought of how to solve this one. I'll be using this solution from now on whether or not anyone else does, so thanks for the suggestion.

Answer 2

This works for me:

git diff **/bar.php 

You may need to run shopt -s globstar first, but I didn't on my system.