Match non-empty lines

grep -v "^\W$" <filename>
I had some trouble removing empty lines from a file (perhaps due to utf-8, as it's the source of all evil), \W did the trick eventually.

0
By: nikc
2009-06-18 08:17:22

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What Others Think

I'm not sure I understand this. \W matches a single non-alphanumeric character. The -v option negates the match. So your command prints all lines that do not consist of a single non-alphanumeric character. Maybe it was a line with MS-DOS line endings, i.e. CR-LF sequences, so the "empty" lines actually contained a single CR character? (Remember that UNIX only considers LF to terminate lines.) Anyway, there are several simple ways to print all non-empty lines (provided you have a UNIX text file with LF line termination). The simplest one is this: grep . file.txt But these work, too: grep -vx "" file.txt awk /./ file.txt sed -n /./p file.txt sed '/^$/d' file.txt tr -s \\n < file.txt echo g/./p | ed -s file.txt ... and many more.
inof · 466 weeks and 3 days ago
My preferred way: grep -v "^$" file.txt
unixmonkey3280 · 466 weeks and 3 days ago

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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