On my linux fedora core 4 system, the man pages for test indicate the
following:
...
[-n] STRING
the length of STRING is nonzero

-z STRING
the length of STRING is
...

Which to me indicates that testing with -n should give the opposite
result of -z.  When executing the following code:[vbcol=seagreen] 
#!/bin/sh

if ( test -z $FOO ) then
echo test -z returns true
else
echo test -z returns false
fi

if ( test -n $FOO ) then
echo test -n returns true
else
echo test -n returns false
fi

if ( test $FOO ) then
echo test returns true
else
echo test returns false
fi

<<<<<<<<<<<<<<<<<<
I get the following result:

test -z returns true
test -n returns true
test returns false

Am I misunderstanding the man pages?

Thanks

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On Fri, 2006-01-20 at 15:20 -0800, ffarzaneh@gmail.com wrote:
> On my linux fedora core 4 system, the man pages for test indicate the
> following:
[...]

Try replacing the '()' with '[]'
--
S. Anthony Sequeira
++
QOTD:
"You want me to put *holes* in my ears and hang things from them?
How...  tribal."
++

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ffarzaneh@gmail.com wrote:
> On my linux fedora core 4 system, the man pages for test indicate the
> following:
> ...
>       [-n] STRING
>              the length of STRING is nonzero
>
>       -z STRING
>              the length of STRING is
> ...
>
> Which to me indicates that testing with -n should give the opposite
> result of -z.  When executing the following code: 
> #!/bin/sh
>
> if ( test -z $FOO ) then
>   echo test -z returns true
> else
>   echo test -z returns false
> fi
>
> if ( test -n $FOO ) then
>   echo test -n returns true
> else
>   echo test -n returns false
> fi
>
> if ( test $FOO ) then
>   echo test returns true
> else
>   echo test returns false
> fi
>
> <<<<<<<<<<<<<<<<<<
> I get the following result:
>
> test -z returns true
> test -n returns true
> test returns false
>
> Am I misunderstanding the man pages?
>
> Thanks
>

Drop the parenthesis. IIRC the parenthesis create a subshell. Also [
is an alias for test, so you can do test -z ... or [ -z ... ]. Make
sure you have a space after [ and before ].

Jerry

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On 20 Jan 2006, in the Usenet newsgroup comp.unix.admin, in article
<1137799214.322257.13390@f14g2000cwb.googlegroups.com>, ffarzaneh@gmail.com
wrote:

>On my linux fedora core 4 system, the man pages for test indicate the
>following:

Doesn't it give examples?

>Which to me indicates that testing with -n should give the opposite
>result of -z.  When executing the following code: 
>#!/bin/sh
>
>if ( test -z $FOO ) then

if ( test -z "$FOO" ) then

Try that - also remember to assign a value to  FOO.

See

31540 Jul 27  2000 Bash-Prog-Intro-HOWTO

and

http://tldp.org/LDP/abs/html/index.html

Old guy

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