Easiest way in Bourne shell to extract strings from a line of text?

Let's say I'm doing a grep and it returns this line:

Invalid value (48) on line 3

How can I easily pull that value 48 into a variable in Bourne shell?

CaptSaltyJack

Posted 2013-08-13T16:34:01.477

Reputation: 1 515

With pure "classic" Bourne Shell commands, or can you use external tools? No Bash or anything recent? – slhck – 2013-08-13T16:35:50.543

Answers

If you are sure that the pattern is always to get the value in the first pair of parenthesis, then cut is your best friend.

myvar=$(echo 'Invalid value (48) on line 3' | cut -d\( -f2 | cut -d\) -f1)

this extracts the value between the parens.

johnshen64

Posted 2013-08-13T16:34:01.477

Reputation: 4 399

$() is not part of SVID and thus not strictly "Bourne Shell" only. It's defined in POSIX though. – slhck – 2013-08-13T18:13:23.360

yes, if it is indeed the original sh, though in most linux distributions /bin/sh is just a symlink to /bin/bash. however, backstick should work, if $() does not. just remove $ and replace () with ``. – johnshen64 – 2013-08-13T18:16:42.680

Yup, just wanted to mention it for completeness since the OP seemed to be very specific about sh and not Bash and companions. – slhck – 2013-08-13T18:18:56.923

echo 'Invalid value (48) on line 3'| awk -F'[()]' '{print $2}'

Etan Reisner

Posted 2013-08-13T16:34:01.477

Reputation: 1 848