Prints a file leaving out all blank lines and comment-only lines

egrep -v "^\s*(#|$)" myfile.cfg
Does not print any line that either: - is empty - contains only spaces or tabs - starts with # - starts with spaces/tabs followed by a #

2
By: dan
2011-12-08 15:25:17

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  • This will first remove any leading white space. If the line then starts with a comment character, it is cleared. If the result is an empty line, it's deleted. This allows for comment lines with leading white space.


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  • The shortest and most complete comment/blank line remover... Any line where the first non-whitespace character is # (ie, indented # comments), and all null and blank lines are removed. Use the alias as a filter: noc /etc/hosts or grep server /etc/hosts | noc Change to nawk depending awk versions. Show Sample Output


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What Others Think

You got your useless cat award. Congratulations
zolden · 341 weeks ago
This, instead of dumping only lines containing only whitespace, will dump lines containing only "s". Probably not real useful, but you never know. :-)
trapperb · 341 weeks ago
Might be useful for boring configs with lots of comments, but as pointed above it needs backslash before that s because, currently it does NOT do what description says.
mwgamera · 340 weeks and 4 days ago
For some reason the backslash does not show up. Here's the command: cat boring.conf | egrep -v "^\s*(#|$)"
dan · 340 weeks and 3 days ago
Or: egrep -v "^\s*(#|$)" boring.conf No need for cat(1).
atoponce · 339 weeks and 3 days ago
Thanks @atoponce, much better. I've modified the command.
dan · 339 weeks and 1 day 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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