How do I exclude the patch header with "git diff"?

Question

For example in the below output of git diff

diff --git a/commands.txt b/commands.txt
index 79e881a..a9588e5 100644
--- a/commands.txt
+++ b/commands.txt
@@ -1,3 +1,7 @@
+this is an example
+abcxyz
+helllo
+wooo
 makeFilePermissionExecutable
 makeOwnedByMyself
 makeFilePermissionEverything

Is it possible to hide the following:

diff --git a/commands.txt b/commands.txt
index 79e881a..a9588e5 100644
--- a/commands.txt
+++ b/commands.txt

And instead just show the filename (commands.txt in this case) instead?

Answer 1

A workaround I found:

Make the following file accessible in your PATH:

customGitDiff

#!/usr/bin/env bash

echo "$(tput setaf 4) $1"
echo -n "$(tput setaf 4)"
printf "%$(tput cols)s"|tr ' ' '-'
diff -u "$1" "$2" | tail -n +3 | colordiff
echo ""

Then you can instruct git to use the following script as your diff tool. It can be globally set by setting the following in your ~/.gitconfig:

[diff]
  external = customGitDiff

One possibly unfortunate limitation of this, is I'm not sure if it uses the same diff algorithm as git diff.

The above provides me with the following output:

Answer 2

git diff etc \
| sed '/^diff /,/^@@/ {
    H;/^@@/!d;z;x
    s".*\n--- a/\([^\n]*.\)+++ b/\1"==> File: \1"
}
'

That's "accumulate all lines in blocks starting ^diff and ending ^@@, and if the file isn't new reformat the header".

Answer 3

git diff | tail -n +5 will produce the output that you desire.

We pipe the output of git diff into tail -n +5 to begin output on line 5. See the man page for tail -n:

   -n, --lines=[+]NUM
          output the last NUM lines, instead of the last  10;  or  use  -n
          +NUM to output starting with line NUM

You'll have to do some additional regex work if you're looking to consolidate --- a/commands.txt and +++ b/commands.txt to a single line.