Diffing files using git

Today I had to find a fast way to compare the contents of two files to see how they compare to each other.

Both of them were well over a thousand lines long therefore mostly similar and I really didn’t want to go through them manually.

My first instinct was to use the git diff command, but they weren’t in a repo yet.

Great… I really didn’t want to go through the hassle of setting up a repo and copying files around etc.

Typically I try to find solutions that already leverage existing tools on my machine.

After a quick search, I turns out I can just pass a --no-index flag to the git diff command.

The command then looks as follows:

git diff [<options>] --no-index [--] <path> <path>

Great, right? This means I don’t need to set up a new git repository for this.

You can omit the --no-index option when running the command in a working tree controlled by Git and at least one of the paths points outside the working tree, or when running the command outside a working tree controlled by Git.¹

Additionally (especially when comparing larger prose files) I can pass in a --word-diff flag so it will even highlight words within lines.

1 Example

Assuming the following two files:

Here’s to the crazy ones.
The misfits.
The rebels.
The troublemakers.

Here’s to the ordinary people.
The ones who fit in.
The everyday folks.
The rule-followers.`

and running

git diff --no-index --word-diff think_different.txt think_normal.txt

I get an output like this

diff --git a/think_different.txt b/think_normal.txt
index b75cfa6..05417e6 100644
--- a/think_different.txt
+++ b/think_normal.txt
@@ -1,4 +1,4 @@
Here’s to the [-crazy ones.-]{+ordinary people.+}
The [-misfits.-]{+ones who fit in.+}
The [-rebels.-]{+everyday folks.+}
The [-troublemakers.-]{+rule-followers.+}