How can I generate a diff for a single file between two branches in github

Question

I need to generate a diff for a single file that will show the differences between two versions, which are actually tags in github. I then want to send this diff to someone via

Answer 1

I used nulltoken's answer to put together a simple convenience script for pulling up a diff between two commits on GitHub from the command line.

You can find the full script on gist, but here are the good bits:

# Parse the following patterns for repo urls to get the github repo url
# https://github.com/owner/repo-name.git
# git@github.com:owner/repo-name.git
BASE_URL="https://github.com/""$(git config --get remote.origin.url | sed 's/.*github\.com[/:]\(.*\).git/\1/')""/compare"

if [[ "$#" -eq 1 ]]; then
  if [[ "$1" =~ .*\.\..* ]]; then
    # Handle "git hubdiff fromcommit..tocommit"
    open "${BASE_URL}/$(git rev-parse "${1/\.\.*/}")...$(git rev-parse ${1/*\.\./})"
  else
    # Handle "git hubdiff fromcommit"
    open "${BASE_URL}/$(git rev-parse "$1")...$(git rev-parse HEAD)"
  fi
elif [[ "$#" -eq 2 ]]; then
  # Handle "git hubdiff fromcommit tocommit"
  open "${BASE_URL}/$(git rev-parse "$1")...$(git rev-parse "$2")"
fi

It accepts as arguments branches, commits, and anything else that can be resolved by git rev-parse. I used open, which only works on macOS for opening webpages, so if you're on a different environment you'll want to tweak that.

As with nulltoken's answer, in order to point to a single file in the diff, you'll have to click on the file's title to make the anchor string appear in the url bar, which you can then copy.