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

Question

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?

With pure "classic" Bourne Shell commands, or can you use external tools? No Bash or anything recent? — slhck, Aug 13 '13 at 16:35

score 1 · Answer 1 · answered Aug 13 '13 at 17:23

1

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.

answered Aug 13 '13 at 17:23

johnshen64

$() is not part of SVID and thus not strictly "Bourne Shell" only. It's defined in POSIX though. – slhck Aug 13 '13 at 18:13
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 Aug 13 '13 at 18:16
Yup, just wanted to mention it for completeness since the OP seemed to be very specific about sh and not Bash and companions. – slhck Aug 13 '13 at 18:18

score 0 · Answer 2 · answered Aug 13 '13 at 17:33

0

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

answered Aug 13 '13 at 17:33

Etan Reisner

2 Answers2