Regex help

Allan · 2009-12-24 10:17:38

Here is my simplified problem...

> teststring="foo=1 foo=('1' '2' \ '3') foo=\"1 2 3\""
> echo $teststring
foo=1 foo=('1' '2' \ '3') foo="1 2 3"

I want to extract the value for these variables (in reality they will not be all "foo"s)...

#brackets
> echo $teststring | grep -o "foo=([^)]*)"
foo=('1' '2' \ '3')
#quotes
> echo $teststring | grep -o "foo=\"[^)]*\""
foo="1 2 3"
#value
> echo $teststring | grep -o "foo=[^\s\(\"]"
foo=1
#all at once...
> echo ${teststring} | grep -o -e "foo=[^\s\(\"]" -e "foo=\"[^)]*\"" -e "foo=([^)]*)"
foo=1
foo=('1' '2' \ '3')
foo="1 2 3"

Now I want to "simply" the grep by combining the regexp... but this fails:

> echo ${teststring} | grep -o -e "foo=([^\s\(\"]|\"[^)]*\"|([^)]*))"

Any hints at what I am doing wrong. Also, I do not want to use awk, perl, ... bash and grep are all.

lolilolicon · 2009-12-24 10:37:40

This works tho:

echo ${teststring} | grep -Eo "foo=([^\s\(\"]|\"[^)]*\"|\([^)]*\))"

Edit: and this:

echo ${teststring} | grep -o -e "foo=\([^\s\(\"]\|\"[^)]*\"\|([^)]*)\)"

The existence of multiple Regexp Standards can be a pain...

Last edited by lolilolicon (2009-12-24 10:41:58)

Xyne · 2009-12-24 10:45:16

Damn, too slow

echo $teststring | grep -o -e "foo=\([^\s\(\"]\|\"[^)]*\"\|([^)]*)\)"

Anyway, you need to escape the capturing parenthesis and the pipe: \( \| \)

@lolilolicon
Yep, multiple standards, with multiple escape requirements etc can drive you crazy.

Allan · 2009-12-24 20:06:18

Thanks... I could not figure this out for the life of me! I had figured that I did not need to escape brackets I normally needed to escape with "grep -e" but did not think I would have to escape others!

Daenyth · 2009-12-27 17:58:13

I'd recommend using grep -P. It's usually faster and more robust than the other versions, oddly.

Allan · 2009-12-28 21:50:36

Daenyth wrote:

I'd recommend using grep -P. It's usually faster and more robust than the other versions, oddly.

Hmmm.... from the man page

This is highly experimental and grep -P may warn of unimplemented features.

I think I will stick with -E for the time being.

Arch Linux

#1 2009-12-24 10:17:38

Regex help

#2 2009-12-24 10:37:40

Re: Regex help

#3 2009-12-24 10:45:16

Re: Regex help

#4 2009-12-24 20:06:18

Re: Regex help

#5 2009-12-27 17:58:13

Re: Regex help

#6 2009-12-28 21:50:36

Re: Regex help

Board footer