Date: Sat, 18 Aug 2007 13:12:23 -0500 From: Derek Ragona <derek@computinginnovations.com> To: Christer Hermansson <mail@chdevelopment.se>, freebsd-questions@freebsd.org Subject: Re: Regular expressions Message-ID: <6.0.0.22.2.20070818130942.02634918@mail.computinginnovations.com> In-Reply-To: <46C726A8.9010404@chdevelopment.se> References: <46C726A8.9010404@chdevelopment.se>
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At 12:04 PM 8/18/2007, Christer Hermansson wrote: >Hi. > >I'm trying to use regular expressions inside a shell script (/bin/sh) on >my freebsd box and can't get it to work so I searched the web and found >http://regexlib.com/RETester.aspx > >On this webpage I could test my pattern "^[A-Za-z0-9_-]+$" and everything >was fine, did exactly what I wanted to do, check that a string only >contains some combination of the characters A-Z, a-z, 0-9, hyphen - and >underscore _. > >I also found some basic example at >http://www.grymoire.com/Unix/Sh.html#uh-88 : > >--------8<--------8<--------8<--------8<--------8<-------- > >#!/bin/sh > >echo "Type in a number" >read ans >number=`expr "$ans" : "([0-9]*)"` >if [ "$number" != "$ans" ]; then >echo "Not a number" >elif [ "$number" -eq 0 ]; then >echo "Nothing was typed" >else >echo "$number is a fine number" >fi > >--------8<--------8<--------8<--------8<--------8<-------- > >The above example doesn't work on my freebsd box. Maybe I need to update >my system, sitting with 6.0R which never been updated. > >Is there anyone who has some advice about how to get regular expressions >to work in FreeBSD shell script ? > >-- > >Christer Hermansson You have a syntax error using expr. Do a man on expr for more details but if you change that line from: number=`expr "$ans" : "([0-9]*)"` to: number=`expr "$ans" : "\([0-9]*\)"` You will get the desired results. Also when debugging scripts remember to add: set -x to your script on the second line, and see what the script lines are actually doing. -Derek -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. MailScanner thanks transtec Computers for their support.
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