shell regex matching help

[Chris F.A. Johnson]

On Tue, 12 Dec 2006, Neil Watson wrote:

> I need help with this script.
>
> #!/bin/bash
>
> HOSTNAME=`hostname`
> SERVICE="db2"
> CLUSTAT=`/usr/sbin/clustat -s ${SERVICE}|tail -n1`
> # Should return:
>  #db2                  your-hostname                 started
>
> echo $HOSTNAME
> echo $SERVICE
> echo $CLUSTAT
>
> if [[ ${CLUSTAT} = ${SERVICE}[:blank:]+${HOSTNAME}[:blank:]+started ]] ; then

if [[ ${CLUSTAT} == ${SERVICE}[:blank:]+${HOSTNAME}[:blank:]+started ]] ; then


    I'd avoid the non-standard [[...]] syntax and use case:

case $CLUSTAT in
      "$SERVICE"*"$HOSTNAME"*started) echo "Node is active";;
      *) echo "Node is not active"; exit 255 ;;
esac

>        echo "Node is active"
>        exit 0;
> fi
>
> # Else node is not active.
> echo "Node is not active"
> exit 255
>
> Output:
> : !./activenode
> tor-lx-hadrian
> db2
> db2 tor-lx-hadrian started
> Node is not active
>
> Why is the match failing?

    Wrong operator.

man bash:

        [[ expression ]]
           ...
               When  the  == and != operators are used, the string to the right
               of the operator is considered a pattern and matched according to
               the  rules  described  below under Pattern Matching.  The return
               value is 0 if the string matches or does not match the  pattern,
               respectively,  and  1 otherwise.  Any part of the pattern may be
               quoted to force it to be matched as a string.

               An additional binary operator, =~, is available, with  the  same
               precedence  as  ==  and  !=.  When it is used, the string to the
               right of the operator is considered an extended regular  expres-
               sion and matched accordingly (as in regex(3)).  The return value
               is 0 if the string matches the pattern, and 1 otherwise.  If the
               regular  expression  is syntactically incorrect, the conditional

-- 
    Chris F.A. Johnson                      <http://cfaj.freeshell.org>
    ===================================================================
    Author:
    Shell Scripting Recipes: A Problem-Solution Approach (2005, Apress)
--
The Toronto Linux Users Group.      Meetings: http://gtalug.org/
TLUG requests: Linux topics, No HTML, wrap text below 80 columns
How to UNSUBSCRIBE: http://gtalug.org/wiki/Mailing_lists