Added diff git-style with color

linux/shell_commands.md

@@ -9,3 +9,11 @@ pv --rate-limit 1M </dev/zero | ssh user@example.net 'cat >/dev/null'
 ## Scripted creation of partitions
 
 Link: https://wiki.ubuntuusers.de/gdisk/#sgdisk
+
+## diff git-style with color
+
+```
+diff --color -u file1 file2
+```
+
+(Source: [StackOverflow](https://stackoverflow.com/a/4857407))