comparing 2 files and removing lines common to both

Question

I have 2 files, source.txt and old.txt. Wanting to compare and remove of lines, So anything in both old.txt and source.txt, is removed from source.txt

source.txt:

abc.com
def.com
ghi.com
123.com
456.com
789.com
700.com
710.com

old.txt:

123.com
700.com
def.com

output (updated source.txt):

abc.com
ghi.com
456.com
789.com
710.com

https://mywiki.wooledge.org/BashFAQ/066 – Jetchisel Apr 07 '23 at 03:28 — Jetchisel, Apr 07 '23 at 03:28

score 1 · Answer 1 · answered Apr 07 '23 at 03:38

1

perl -ne'
   BEGIN { local $/; ++$remove{ $_ } for split /^/m, <> }
   print if !$remove{ $_ };
' old.txt source.txt

answered Apr 07 '23 at 03:38

ikegami

367,544
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score 1 · Answer 2 · edited Apr 07 '23 at 15:22

1

Why not just use grep(1):

grep -v -f old.txt source.txt

edited Apr 07 '23 at 15:22

TLP

66,756
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92
149

answered Apr 07 '23 at 05:35

ernix

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comparing 2 files and removing lines common to both

2 Answers2