How do I delete lines beginning with a #, given that there can be whitespace on the left and right of the #?
# Master socket provides access to userdb information. It's typically 
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6 Answers
This seems to work, but I've not given deep thought to it:
sed -e '/^[[:space:]]*#/d' 
You can use grep for that
grep -vh '^[[:space:]]*#' filename Since, as I presume, you are stripping comments from some file, you might also consider removing empty lines, which expands the above to:
grep -vh '^[[:space:]]*\(#\|$\)' filename awk solution is to invert matching your pattern.
$> cat ./text elephant # Master socket provides access to userdb information. It's typically zoo #ok penguin # ! $> awk '!/^(\ )*#/ {print $0}' ./text elephant zoo penguin - 5No need to escape the space character, no need to capture the space character, no need to specify the default action:
awk '!/^ *#/' ./text.manatwork– manatwork2011-11-28 15:42:07 +00:00Commented Nov 28, 2011 at 15:42 -
awk '/^ *#/{next}1' fileshould be good enough.jaypal singh– jaypal singh2011-12-23 05:01:28 +00:00Commented Dec 23, 2011 at 5:01
perl -ne 'print if ! /^\s*#/' ./text 
- hi @Peter-john-acklam, would this work when the code is followed by # comment?Nikhil Mulley– Nikhil Mulley2012-01-14 10:47:09 +00:00Commented Jan 14, 2012 at 10:47
Using the sample data posted by ДМИТРИЙ МАЛИКОВ...
$ grep -vPh '^\s*#' filename.txt | grep -Po '\w+' elephant zoo penguin I prefer using pcre with grep so I use the -P switch for grep (must be GNU grep). The second grep is pure sugar to give you the words with no white-space. It would also "remove" empty lines.
$ perl -pi -e '$_="" if /^\s*#/' filename 
- That's not good - doesn't delete lines, and clears lines like
a#bMat– Mat2011-12-12 04:23:28 +00:00Commented Dec 12, 2011 at 4:23