sed delete lines not matching patterns in txt file

Question

I'm dealing with a txt file that lists a bunch of other txt files, a lot of which I have wrongfully duplicated.

I'm on macOS so the lines listing the duplicated files all end with the pattern (NUMBER).txt. I want to delete all the lines that don't contain this pattern.

I came up with this command to test the regex but it does not work as it also prints the lines that end with (WORD).txt:

sed '/\(\d\)\.txt$|\(\d\d\)\.txt$|\(\d\d\d\)\.txt$/p' file.txt

I know I'm missing something but I can't figure out what... Thanks for your help!

See Why does my regular expression work in X but not in Y? - it will answer several issues like which metacharacters should be escaped, \d not supported, etc — Sundeep, Jul 04 '20 at 09:55
\d is not (traditional) sed regex syntax; instead it's just a d; did you try to read the sed manual page? — U. Windl, Oct 08 '21 at 07:55

Francesco · Answer 1 · 2020-07-04T08:41:41.070

0

This should work:

sed -E -n '/.*[0-9]+\.txt$/p' file.txt

If you take a look at info sed, at the paragraph 2.1 you will find some examples of how to use the combination sed -n '...p'.

The above command prints to stdout. If you want to modify the file in place add the -i option.

edited Jul 04 '20 at 08:41

answered Jul 04 '20 at 08:36

Francesco

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sed delete lines not matching patterns in txt file

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