How to use a buffer as an argument for a grep command
reddit / emacs

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seidenkaufman · 2022-06-13 15:35

From the command line, I can get `grep` to use the lines in a file to
search through another file by using the `-f` flag. For example, `grep
-f file1 file2`

In Emacs, is there a way to use `grep` such that the contents of a
buffer (not necessarily saved to file) would be used in the same way
as `file1` in the command above?

Thank you!

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_viz_ · 2022-06-13 15:50

Use occur or multi-occur instead.  The former is bound to M-s o.

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ambihelical · 2022-06-13 15:52

You can use shell-command-on-region (M-|) along with using - (single
hyphen) as the file name given to grep.  So you would type:

M-| grep -f-  file-to-grep

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seidenkaufman · 2022-06-13 16:53

Thanks, this worked brilliantly!

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dpoggio · 2022-06-14 02:46

This is what I would use. You can even use multiple regexes and keep
seeing the outcome as you type. Neat.