4

I have a list of usernames that are in a text file. I update this file and commit it. I am looking for a way to get a list of the changes since the last commit.

I do not want any diff formatting at all, I just want to get an output that has usernames one per line (as they are added to each commit) since the last commit.

I can't find a setting that will remove all the git diff syntax from the output so it's purely a list new lines added only.

Example

Original file:

user1
user2
user3

I then add 

user4
user5

Then commit.

I want to be able to do a git diff and see only:

user4
user5
andcoz
  • 17,130
Michael
  • 141

2 Answers2

6

You could grep the diff output combining lookahead/lookbehind:

git diff --unified=0 | grep -Po '(?<=^\+)(?!\+\+).*'
  • (?<=^\+) is a positive lookbehind for line starting with +
  • (?!\+\+) is a negative lookahead to prevent matching files headers starting with +++ a/path/to/file.

The --unified=0 git option is just there to reduce the numbers of line to filter removing diff context, it is optional though.

There is probably better, I'm not fluent in PCRE.

kaliko
  • 583
3

Borrowing --unified=0 from kaiko answer I came to:

git diff HEAD^ HEAD --unified=0 | tail +6 | sed -e 's/^\+//'
Patrick Mevzek
  • 3,180
  • Should't it be -6. +6 gives: tail: cannot open '+6' for reading: No such file or directory. – pevik Dec 08 '22 at 19:21
  • @pevik Depends on your tail flavor... If +6 is not ok, try --lines=+6 but look at the specific manual of your tail command. -6 and +6 have a different meaning, -6 would mean last 6 lines (because tail "starts" from the end) where +6 means "output everything from line 6 to end". – Patrick Mevzek Dec 08 '22 at 22:37
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    You have POSIX definition of tail at https://pubs.opengroup.org/onlinepubs/9699919799/utilities/tail.html#tag_20_125 . In theory the correct writing should be -n +6. – Patrick Mevzek Dec 08 '22 at 22:41
  • Sure, -n +6 works for various implementations (coreutils, busybox). But plain +6 works on busybox, but not on coreutils implementation. – pevik Dec 09 '22 at 09:13