[X-Unix] bash problem: `expr index $somestring somepattern` fails

[Steffen Lund Hokland]

Hi,

I'm writing a bash script and needed something along the lines of:

`expr index $somestring somepattern`

for parsing a text string. This is described in:
'Advanced Bash-Scripting Guide: An in-depth exploration of the art of 
shell scripting' version 2.7.7. However when running the command above 
i get an error:

expr: syntax error

Apparently this happens whenever using 'expr' with 'index', 'length', 
'match' and 'substring' this occurs. I've tried running the example 
script 12.9 (the file is called ex45.sh in my download), and get this 
error message whenever `expr index/length/match/substring ......` 
occurs.

Does anybody know what's wrong. I know that there are far better ways 
of parsing a text string (awk, perl...), but it just bugs me....

Thanks in advance,
Steffen