Question

I’m trying to use egrep with a regex pattern to match whitespace.

I’ve used RegEx with Perl and C# before and they both support the pattern \s to search for whitespace. egrep (or at least the version I’m using) does not seem to support this pattern.

In a few articles online I’ve come across a shorthand [[:space:]], but this does not seem to work. Any help is appreciated.

Using: SunOS 5.10

Answer 1

I see the same issue on SunOS 5.10. /usr/bin/egrep does not support extended regular expressions.

Try using /usr/xpg4/bin/egrep:

$ echo 'this line has whitespace thislinedoesnthave' | /usr/xpg4/bin/egrep '[[:space:]]' this line has whitespace 

Another option might be to just use perl:

$ echo 'this line has whitespace thislinedoesnthave' | perl -ne 'chomp;print '$_\n' if /[[:space:]]/' this line has whitespace