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May 19, 2015 - A Look At The New Commandlinefu
I've put together a short writeup on what kind of newness you can expect from the next iteration of clfu. Check it out here.
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Match non-empty lines

Terminal - Match non-empty lines
grep -v "^\W$" <filename>
2009-06-18 08:17:22
User: nikc
Functions: grep
Match non-empty lines

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.


There is 1 alternative - vote for the best!

Terminal - Alternatives

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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.

Comment by inof 456 weeks and 5 days ago

My preferred way:

grep -v "^$" file.txt
Comment by unixmonkey3280 456 weeks and 5 days ago

Your point of view

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