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aiman

08-25-2011 02:30 PM

New to regex, need help

Hi guys am new to regex and am stuck, I need to extract text between first hyphen and first .(dot) from my hostname which is of the type

abcdqa-asd-sd.local

I want to get asd-sd through regex, the pattern of hostname always remains the same as stated.

Please help
Thanks

AlucardZero

08-25-2011 03:00 PM

Useful site: http://www.regular-expressions.info/

You should mention where you are using regexes for the best help. Basic REs are less than Extended REs are less than Perl Compatible REs.

Assuming you're using Perl you want

Code:

$string =~ /-(.+)\./;

print "$1\n";

Pretty simple regex.

Tinkster

08-25-2011 04:00 PM

Or with sed

Code:

echo abcdqa-asd-sd.local | sed -r 's/^[^-]+-([^.]+).*/\1/'

asd-sd

PTrenholme

08-25-2011 05:52 PM

Code:

$ echo abcdqa-asd-sd.local | gawk '{$0=gensub(/^[^-]+-([^.]+).*/,"\\1","n");print}'

asd-sd

And your could do gawk '{$0=gensub(/^[^-]+-([^.]+).*/,"\\1","n");print}' <input> > <output> to process a file. (Lines that don't match the expression would be copied verbatim to the output.)

kurumi

08-25-2011 11:21 PM

If you have Ruby(1.9+) or any language that supports splitting strings with limits.

Code:

string="abcdqa-asd-sd.local"

puts string.split("-",2)[-1].split(".")[0]

No regex needed. First split the string on "-". The parameter "2" means split on 2 fields. Then split on the last field ( the text you want is somewhere there) on "." and get the first element.

Or else, you can do it with bash

Code:

$ string="abcdqa-asd-sd.local"

$ echo ${string#*-}

asd-sd.local

$ string=${string#*-}

$ echo ${string%%.*}

asd-sd

grail

08-26-2011 12:15 AM

Awk alternative:

Code:

echo "abcdqa-asd-sd.local" | awk -F"[-.]" '{print $2,$3}' OFS="-"

kurumi

08-26-2011 12:24 AM

Quote:

Originally Posted by grail (Post 4453720)

Awk alternative:

Code:

echo "abcdqa-asd-sd.local" | awk -F"[-.]" '{print $2,$3}' OFS="-"

Nice. But may not work if there are multiple hyphens.....:)

David the H.

08-26-2011 01:45 AM

In bash, using full regex:

Code:

string="abcdqa-asd-sd.local"

re='^[^-]+-([^.]+)\.'



[[ "$string" =~ $re ]]



echo "${BASH_REMATCH[1]}"

grail

08-26-2011 02:01 AM

Quote:

Nice. But may not work if there are multiple hyphens

True enough, but simple change:

Code:

echo "abcdqa-asd-sd.local" | awk -F"[-.]" '{print $2,$(NF-1)}' OFS="-"

kurumi

08-26-2011 04:17 AM

Quote:

Originally Posted by grail (Post 4453783)

True enough, but simple change:

Code:

echo "abcdqa-asd-sd.local" | awk -F"[-.]" '{print $2,$(NF-1)}' OFS="-"

nice, but again, it will not work if there is string like "abcdqa-asd---jgsd.local". (of course, I am being picky here :) )

kurumi

08-26-2011 04:22 AM

Quote:

Originally Posted by David the H. (Post 4453765)

In bash, using full regex:

Code:

string="abcdqa-asd-sd.local"

re='^[^-]+-([^.]+)\.'



[[ "$string" =~ $re ]]



echo "${BASH_REMATCH[1]}"

nice, but that won't work with strings like "-abcdqa-asd---jgsd.local" (yes, I am being picky :) )

grail

08-26-2011 06:28 AM

Quote:

nice, but again, it will not work if there is string like "abcdqa-asd---jgsd.local". (of course, I am being picky here )

Please pick away as I always like a challenge :)

Code:

echo "abcdqa-asd---jgsd.local" | awk -F. '{print gensub(/[^-]*-/,"","1",$1)}'

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