Git: Show commits that have touched specific text in a file

If you want to find the commits that touched a specific text in a file,

use git log -S 'text in the code' -- path/to/file.

Here is an example, where the move of the convert_number_column_value(value) method in active record is traced (simplified output):

git log -n 1 --pretty=oneline -S 'convert_number_column_value(value)' -- activerecord/lib/active_record/base.rb
ceb33f84933639d3b61aac62e5e71fd087ab65ed Split out most of the AR::Base code into separate modules :cake:

git show ceb33f84933639d3b61aac62e5e71fd087ab65ed

 activerecord/lib/active_record/base.rb
 -      def convert_number_column_value(value)		
 -        if value == false		
 -          0		
 -        elsif value == true		
 -          1		
 -        elsif value.is_a?(String) && value.blank?		
 -          nil		
 -        else		
 -          value		
 -        end		
 -      end

 activerecord/lib/active_record/attribute_methods/write.rb
 +        def convert_number_column_value(value)
 +          if value == false
 +            0
 +          elsif value == true
 +            1
 +          elsif value.is_a?(String) && value.blank?
 +            nil
 +          else
 +            value
 +          end
 +        end

https://makandracards.com/makandra/42705-git-show-commits-that-have-touched-specific-text-in-a-file

-S<string>
Look for differences that change the number of occurrences of the specified string (i.e. addition/deletion) in a file. Intended for the scripter’s use.
It is useful when you’re looking for an exact block of code (like a struct), and want to know the history of that block since it first came into being: use the feature iteratively to feed the interesting block in the preimage back into -S, and keep going until you get the very first version of the block.
Binary files are searched as well.
-G<regex>
Look for differences whose patch text contains added/removed lines that match <regex>.
To illustrate the difference between -S<regex> --pickaxe-regex and -G<regex>, consider a commit with the following diff in the same file:
```
+    return !regexec(regexp, two->ptr, 1, &regmatch, 0);
...
-    hit = !regexec(regexp, mf2.ptr, 1, &regmatch, 0);
```
While git log -G"regexec\(regexp" will show this commit, git log -S"regexec\(regexp" --pickaxe-regex will not (because the number of occurrences of that string did not change).
Unless --text is supplied patches of binary files without a textconv filter will be ignored.
See the pickaxe entry in gitdiffcore[7] for more information.

https://git-scm.com/docs/git-log

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