One of the cool features built into #emacs is narrowing. If you have a file with many lines, but you only need to work on a single function or portion of the file, you can select the region you want to work on and have only that in the buffer, you can still save and commit your changes while narrowing down.
https://imgur.com/a/15mZ7Ty
https://imgur.com/a/15mZ7Ty
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