Subject: Re: [ast-users] Re: [bbx-list] Re: old SCO script not working in Suse
Linux
--------
> On another, non-ksh related, mailing list, someone wrote:
>
> > <> is a legal operator under SCO's old version of ksh, and also under
> > Linux's bash.
> >
> > This runs fine under 5.0.7 and ksh:
> >
> > aa="OK"
> >
> > if [ "$aa" <> "XX" ]
> > then
> > echo "Was not XX"
> > fi
> >
> > The echo line displays when run.
>
> This indeed works as he describes, but the case where the two items
> being tested are equal does not. I.e.:
>
> aa="OK"
>
> if [ "$aa" <> "OK" ]
> then
> echo "Was not XX"
> fi
>
> This still prints "Was not XX". I don't believe <> was ever valid
> syntax, so what is really going on here. Are the <> operators being
> interpreted as IO redirection? Why does the shell not generate an error?
Since
[ "$aa" <> "XX" ]
is an ordinary command, unlike [[...]], it is parsed with the normal rules.
Redirection operators can be anywhere on the line so that this is equivalent
to
[ "$aa" ] <> "XX"
The <> opens XX for reading and writing.
This returns true if $aa is not empty and if $aa does not begin with -
and is not ! in which case it could be an error.
David Korn
[EMAIL PROTECTED]
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