RE: Bash scripting problem

["Christophe ABRIAL" <christophe.abrial@lsafrance.com>]

Hello,

If you read the man about bash, you will find out that all commands after a
pipeline are executed in a subshell.
It's not a bash bug !

Perhaps, if you try this :

#!/bin/bash -e

    found_driver=0
    echo -n "Starting sound driver: "
    while read line; do
      if /sbin/modprobe $line >/dev/null 2>&1; then
	echo "$line"
	found_driver=1
	echo "DEBUG1: found_driver=$found_driver"
      fi
      echo "DEBUG2: found_driver=$found_driver"
    done < awk '/^alias +snd-card-[0-9]/ {print $3}' /etc/modules.conf
    echo "DEBUG3: found_driver=$found_driver"

Hope it's help!

Christophe Abrial
LSA France
Systems and Networks Solutions

-----Message d'origine-----
De : Martin Fluch [mailto:fluch@rock.helsinki.fi]
Envoye : mardi 2 mai 2000 09:43
A : debian-user@lists.debian.org
Objet : Bash scripting problem


Hi all!

On my woody box I ran into the following problem:

After I had problem with the /etc/init.d/alsa script I started to track
down the problem and finaly ended with the following script, which doesn't
work like I expect:

#!/bin/bash -e

    found_driver=0
    echo -n "Starting sound driver: "
    awk '/^alias +snd-card-[0-9]/ {print $3}' /etc/modules.conf | \
    while read line; do
      if /sbin/modprobe $line >/dev/null 2>&1; then
	echo "$line"
	found_driver=1
	echo "DEBUG1: found_driver=$found_driver"
      fi
      echo "DEBUG2: found_driver=$found_driver"
    done
    echo "DEBUG3: found_driver=$found_driver"

When I execute this, I get the following output:

root@seneca:/etc/init.d> ./alsa.debug
Starting sound driver: snd-card-cs4236
DEBUG1: found_driver=1
DEBUG2: found_driver=1
DEBUG3: found_driver=0

What me puzzles is: why is finaly $found_driver reseted to 0? Is this a
bash bug (bash --version gives "GNU bash, version 2.04.0(1)-release
(i386-pc-linux-gnu) ...")?

Martin



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