OK, ZONK and space oddysey

node · #1 (**permalink**) 03-27-04, 00:20

Code:

#!/bin/sh

STRING="hal,kohal,obahalta,hal9000"
if [ `echo $STRING | grep hal` ]; then
  echo OK
else
  echo ZONK
fi

STRING has inside "hal"
even if i change STRING to "kohal,obahalta,hal9000"
i always get OK
how to recognize if there is in STRING exactly 'hal' separated by comas?

aigles · #2 (**permalink**) 03-27-04, 05:48

Try the following Regular Expression with egrep (or grep -E) : ^(.*,)?hal(,.*)$

This RE recognizes the following strings (_ is any char):
___,hal,___
hal,___
___,hal
hal

Code:

if echo "$STRING" | egrep -q '^(.*,)?hal(,.*)?$' ; then
  echo OK
else
  echo ZONK
fi

With ksh you can use the = operator instead of grep, with the pattern : ?(*,)hal?(,*)

Code:

#!/usr/bin/ksh
if [[ "$STRING" = ?(*,)hal?(,*) ]] ; then
  echo OK
else
  echo ZONK
fi

If you really want to recognize only the first form (___,hal,___), modify your RE by ',hal,'

Code:

#!/bin/sh

STRING="hal,kohal,obahalta,hal9000"
if [ `echo $STRING | grep ',hal,` ]; then
  echo OK
else
  echo ZONK
fi

node · #3 (**permalink**) 03-27-04, 08:38

Great!!!
This is it what I was was looking for!!!
Thank you!

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