Don't use grep -P about eless HOT 8 CLOSED

Working!

Note that $3 does not need to be quoted.

You also can use non-capturing parenthesis around the groups you don't want to capture, then use print $1:

perl -ne '/^Help on (?:.+ in )*(?:module|package) (.*)(?=:$)/ and print $1'

Just an FYI.

from eless.

Or instead of using Perl regexes (-P), just use perl

That's interesting.. didn't think of that.

Also if you use egrep then you don't have to escape any of ()+.

I believe it's more canonical to use grep -E instead of egrep? In any case, I first became a fan of grep -E (and sed -r) and then grep -P.

I'll have to find some time to research replacing the grep -P and sed -r.

Thanks for all that info.

from eless.

I believe it's more canonical to use grep -E instead of egrep?

Not sure.

from eless.

Note sure

Oh well, from man grep (of course GNU grep):

In addition, two variant programs egrep and fgrep are available. egrep is
the same as grep -E. fgrep is the same as grep -F. Direct invocation as
either egrep or fgrep is deprecated, but is provided to allow historical
applications that rely on them to run unmodified.

from eless.

I'll need to spend some time understanding how to convert grep -Po .. expressions to perl -ne ...

Help me out if you already have the answer :)

> echo "Help on Quitter in module _sitebuiltins object:" | \grep -Po '^Help on (.+ in )*(module|package) \K(.*)(?=:$)'
_sitebuiltins object

> echo "Help on Quitter in module _sitebuiltins object:" | \perl -ne '/^Help on (.+ in )*(module|package) \K(.*)(?=:$)/ and print'
Help on Quitter in module _sitebuiltins object:

Need to figure out out to make perl return only the stuff after \K and before (?= .. ) (that's what the -o in grep does.. and the -P makes it understand \K and look-ahead).

from eless.

OK, this worked:

echo "Help on Quitter in module _sitebuiltins object:" | \perl -ne '/^Help on (.+ in )*(module|package) (.*)(?=:$)/ and print "$3"'

from eless.

Please test the replace-grep-with-perl branch.

from eless.

Note that $3 does not need to be quoted. You also can use non-capturing parenthesis around the groups you don't want to capture,

Thanks, of course. Completely forgot that elisp regexp is not the only place you could do that :)

from eless.