Re: Using quotes in bash script parameters

[Cédric Lucantis <omer@no-log.org>]

Le mercredi 14 mars 2007 02:07, Cédric Lucantis a écrit :
> Le mercredi 14 mars 2007 01:04, Marco De Vitis a écrit :
> > Hi,
> > this is not strictly Debian-related, but I'm doing it on Etch, so... :)
> >
> > Let's say I'm writing a script like this:
> > > #! /bin/bash
> > >
> > > SUBJECT="This is a test mail"
> > > WARNMSG="An error occurred"
> > > WARNCMD="mail -s \"${SUBJECT}\" root"
> > >
> > > echo "echo $WARNMSG | $WARNCMD"
> > > echo $WARNMSG | $WARNCMD
> >
> > Everything works fine if I enter the equivalent command line:
> >
> > 	echo "An error occurred" | mail -s "This is a test mail" root
> >
> > A mail is sent to root with subject "This is a test mail" and body "An
> > error occurred".
> >
> > The script should produce the same effect, but instead, when I run it,
> > it sends a mail with subect <"This> and body "An error occurred" to the
> > following users:
> >
> > is
> > a
> > mail
> > , root, test
> >
> > ....although the command line printed by the first echo statement looks
> > perfect.
> >
> > It'a problem which has been bugging me for a while. I usually find some
> > workaround, but I'm a bit tired now. An I suppose it should be some kind
> > of FAQ... although I couldn't find anything around.
> >
> > I already tried with single quotes, I tried escaping them, I tried
> > escaping the spaces in the subject... to no avail.
> >
> > Any clues?
> > Thanks.
>
> eval does the trick:
>
> SUBJECT="This is a test mail"
> WARNMSG="An error occurred"
> WARNCMD="mail -s \"${SUBJECT}\" root"
> echo "echo $WARNMSG | $WARNCMD"
> eval $WARNMSG | $WARNCMD

oops, sorry, quotes are required here:

eval "$WARNMSG | $WARNCMD"

-- 
Cédric Lucantis