How does one compare strings in zsh?

[Zubin Dittia]

I haven't used zsh before, and I've been having great difficulty
trying to get it to compare two strings. I read the man pages
several times, and this is what I came up with:
TESTSTRING="test string"
if ( [[ $TESTSTRING = "test string" ]] ) {
echo 'it works'
} else {
echo 'it does not work'
}
and unfortunately this does not work. I'd be grateful if some of
you shell gurus could help me out. Please e-mail your replies to
zu...@dworkin.wustl.edu
Thanks in advance.
-Zubin.

PS: I've been running zsh in an xterm, and several times it has died
with a segmentation fault. It also misbehaves sometimes when
displaying commands spanning more than one line from the history.
Does anyone know why this happens or how I can go about correcting
it?

[Eric De Mund]

zu...@dworkin.wustl.edu (Zubin Dittia) writes:
>I haven't used zsh before, and I've been having great difficulty
>trying to get it to compare two strings. I read the man pages
>several times, and this is what I came up with:
> TESTSTRING="test string"
> if ( [[ $TESTSTRING = "test string" ]] ) {
> echo 'it works'
> } else {
> echo 'it does not work'
> }
>and unfortunately this does not work.

use [[...]] to test attributes of files and to compare strings. use
((...)) to test arithmetic expressions. example:

foo() {
if (( $# == 0 ))
then
echo usage: foo \<string\>
else
if [[ $1 = duck ]]
then
echo it\'s a duck
else
echo it\'s not a duck
fi
fi
}

% foo
usage: foo <string>
% foo cat
it's not a duck
% foo duck
it's a duck
%

see the ARITHMETIC EVALUATION and CONDITIONAL EXPRESSIONS section of
the zsh (v2.1.0) man page.

>PS: I've been running zsh in an xterm, and several times it has died
> with a segmentation fault. It also misbehaves sometimes when
> displaying commands spanning more than one line from the history.
> Does anyone know why this happens or how I can go about correcting
> it?

sorry, can't help you here. i don't experience this.

eric de mund
e...@netcom.com

[Zubin Dittia]

In my original posting, I had claimed that the following sequence didn't
work for me:

TESTSTRING="test string"
if ( [[ $TESTSTRING = "test string" ]] ) {
echo 'it works'
} else {
echo 'it does not work'
}

I received a number of replies saying that this worked fine for others,
so I went back and recompiled zsh. Surprisingly, it worked fine that time.
The only difference between the two compiles was that I had used
"gcc -traditional" the first time, and "cc" the second. Apparently, zsh
misbehaves when compiled with gcc. Since I don't know the technical
differences between the two compilers (I normally prefer using gcc),
I can't speculate on the possible cause for this.

-Zubin.

[Jonathan Hardwick]

zu...@dworkin.wustl.edu (Zubin Dittia) writes:
> The only difference between the two compiles was that I had used
> "gcc -traditional" the first time, and "cc" the second. Apparently, zsh
> misbehaves when compiled with gcc.

Counter-example: zsh runs fine on a DECstation 2100 when compiled with
V2.0 gcc -traditional -O2. It also gets a 10% size reduction over zsh
compiled with ultrix cc -O3. What machine and version of gcc are you
using?

Jonathan H.

ObShell : implementing Mach's setpath(1) as a single zsh function.