I'm trying to use egrep w/ a regex pattern to match whitespace. I've used RegEx w/ perl and C# before and they both support the patter \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
$ cat > file
this line has whitespace
thislinedoesnthave
$ egrep [[:space:]] file
this line has whitespace
Works under debian.
For Solaris, isn't there an "eselect" like (see gentoo) or alternatives file to set default your egrep version?
Have you tried grep -E, because if the egrep that is on your path is not the good one, maybe grep is.
Maybe you should protect the pattern with quotes (if bash, or anything equivalent for the shell you are using).
[ and ] may have special meaning for the shell.
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
If you're using 'degraded' versions of grep (I quote the term because most UNIX'es I work on still use the original REs, not those fancy ones with "\s" or "[[:space:]]" :-), you can just revert to the lowest form of RE.
For example, if :space: is defined as spaces and tabs, just use:
egrep '[ ^I]' file
That ^I is an actual tab character, not the two characters ^ and I.
This is assuming :space: is defined as tabs and spaces, otherwise adjust the choices within the [] characters.
The advantage of using degraded REs is that they should work on all platforms (at least for ASCII; Unicode or non-English languages may have different rules but I rarely find a need).