This script helps you to answers questions like:
How did this variable in this file come to have the value it has now?
Or just to see how a certain line became what it is now in a file. This is helpful when working on code from others and it is not clear why a certain "something" is as it is in a file.
See the script for more details.
| #!/bin/bash | |
| # | |
| # Script that can be used to show all commits where a specific regex is matched | |
| # for a single file. | |
| # This can be used for example to see the history of how a single variable or | |
| # pattern had evolved to what it current state is. | |
| # | |
| # This is an expansion of: https://stackoverflow.com/a/9935417 | |
| # | |
| # For example I have a piece of code that sets a variable to specifc value, but | |
| # no one knows why it has that value. If the variable is called 'foobar' for | |
| # example and it is in a file baz.py this script can help find every commit | |
| # where this name occured in the commit diff: | |
| # | |
| # gitRegexHistory 'foobar' baz.py | |
| # | |
| # Be as specific as possible with the regex search to limit the hits more | |
| # precisely. | |
| ME=$(basename $0) | |
| SEARCH="$1" | |
| shift | |
| FILE="$1" | |
| shift | |
| function showhelp() { | |
| cat - << __HERE__ | |
| Usage: $ME 'search-string-regex' file [args] | |
| where: | |
| 'search-string-regex': regex passed to the -G arg for 'git log' to search | |
| file: the file name to show the history for | |
| [args]: any further args are passed to 'git log' as args verbatim | |
| __HERE__ | |
| } | |
| # Validate params | |
| [ -z "$SEARCH" ] && showhelp && exit 1 | |
| [ -z "$FILE" ] && showhelp && exit 1 | |
| [ ! -f "$FILE" ] && showhelp && exit 1 | |
| # Find all commits where the patch text contains add/remove lines that matches | |
| # the search pattern | |
| for c in $(git log -G "$SEARCH" --format=%H -- $FILE); do | |
| # Grep the commit for this file for the same pattern | |
| git --no-pager grep -e "$SEARCH" --heading $* $c -- $FILE | |
| echo | |
| done | |