[CentOS] perl script part eval help please?

Ralph Angenendt ra+centos at br-online.de
Sun Aug 27 08:56:23 UTC 2006


Email Lists wrote:
> Greetings
> 
> Im am not a perl programmer yet I am trying to learn and am debugging
> someone elses perl run script for use on a centos production box I have and
> I came across this
> 
> elif [ -z "${SMTP_CDB:-}" ]

That's not perl, that is part of a shell script. 

${SMTP_CDB:-} returns an empty string if the Variable $SMTP_CDB is not
set. See "Parameter Expansion" in the manual page of bash. And "test -z
$string" returns true, if $string is empty.

Regards,

Ralph
-- 
Ralph Angenendt......ra at br-online.de | .."Text processing has made it possible
Bayerischer Rundfunk...80300 München | ....to right-justify any idea, even one
Programmbereich.Bayern 3, Jugend und | .which cannot be justified on any other
Multimedia.........Tl:089.5900.16023 | ..........grounds." -- J. Finnegan, USC
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: not available
URL: <http://lists.centos.org/pipermail/centos/attachments/20060827/6a2f924e/attachment.sig>


More information about the CentOS mailing list