Bourne shell "if" syntax

[dteske at freebsd.org]

> -----Original Message-----
> From: Devin Teske [mailto:devin.teske at fisglobal.com] On Behalf Of
> dteske at freebsd.org
> Sent: Monday, June 10, 2013 11:59 AM
> To: lconrad at go2france.com; freebsd-questions at freebsd.org
> Cc: Devin Teske
> Subject: RE: Bourne shell "if" syntax
> 
> 
> 
> > -----Original Message-----
> > From: owner-freebsd-questions at freebsd.org [mailto:owner-freebsd-
> > questions at freebsd.org] On Behalf Of lconrad at go2france.com
> > Sent: Monday, June 10, 2013 11:53 AM
> > To: freebsd-questions at freebsd.org
> > Subject: Bourne shell "if" syntax
> >
> >
> >
> > script fragment:
> >
> > PTR=`dig @some.dns +short +norec -x a.b.c.d`
> >
> > echo "$PTR"
> >
> > if  [  "$PTR"  ==  ""  ]  ;  then
> >
> 
> if [ "$PTR" = "" ]; then
> 
> or
> 
> if [ -z "$PTR" ]; then
> 
> or
> 
> if [ "$PTR" ]; then
> 

err, that should have been:

or

if [ ! "$PTR" ]; then

-- 
Devin


> but _NOT_
> 
> if [ "$PTR" == "" ]; then
> 
> --
> Devin
> 
> 
> > echo "$PTR" >> /path/to/PTR_absent.txt
> >
> > fi
> >
> > ===========
> >
> > output for an IP:
> >
> >
> > a-b-c-d.domain.net.
> > [: a-b-c-d.domain.net.: unexpected operator
> >
> > thanks
> > Len
> >
> >
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