(code) One-liner removes whitespace-only lines from text file

Perl one-liner to remove from a text file all lines that contain only whitespace.

Other Ways To Do It (mostly not one-liners) can be found at the thread "How do I remove blank lines from text files?".

Hmmm... personally, I like Ovid's example below better than mine. It *does* seem more directly recognizable.

perl -i.bak -ne 'print unless /^\s+$/' file.txt

Comment on (code) One-liner removes whitespace-only lines from text file Download Code

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(Ovid) Re: One-liner removes whitespace-only lines from text file by Ovid (Cardinal) on Dec 19, 2001 at 02:32 UTC
`perl -i.bak -ne 'print if /\S/' file.txt` [download] Seems a bit more intuitive to me :) Cheers, Ovid Join the Perlmonks Setiathome Group or just click on the the link and check out our stats.	[reply] [d/l]
Re: One-liner removes whitespace-only lines from text file by jmcnamara (Monsignor) on Dec 19, 2001 at 14:00 UTC
This is attributable to abigail: `perl -lp00ee file` Update: As chip points out, this one-liner removes blank lines and not whitespace-only lines. -- John.	[reply] [d/l]
Re: Re: One-liner removes whitespace-only lines from text file by chip (Curate) on Dec 19, 2001 at 14:39 UTC
Well, 10 out of 10 for cleverness, but abigail's trick only removes empty lines, i.e. those that match /^$/; but the original requirement was to remove lines made up of any combination of whitespace. -- Chip Salzenberg, Free-Floating Agent of Chaos	[reply]
Re: One-liner removes whitespace-only lines from text file by FoxtrotUniform (Prior) on Dec 19, 2001 at 02:21 UTC
This snippet removes all non-empty lines containing only whitespace, but I don't think that's particularly intuitive behaviour. If I want to remove all "blank" lines from a file, I probably want: `perl -i.bak -ne 'print if /\S/' file.txt` [download] and if I want to get rid of all the lines with "useless" whitespace, I probably want to collapse them to empty lines: `perl -i.bak -ne 's/^\s+$//;print' file.txt` [download] Update: Changed first one-liner to Ovid's for readability. `-- :wq`	[reply] [d/l] [select]