The equivalent of “stty -echo” for zsh

export in zsh is shorthand for typeset -gx, where the attribute g means “global” (as opposed to local to a function) and the attribute x means “exported” (i.e. in the environment). Thus:

typeset +x GREP_OPTIONS

This also works in ksh and bash.

If you never export GREP_OPTIONS in the first place, you don't need to unexport it.

You can also use the indirect, portable way: unsetting a variable unexports it. In ksh/bash/zsh, this doesn't work if the variable is read-only.

tmp=$GREP_OPTIONS
unset GREP_OPTIONS
GREP_OPTIONS=$tmp

stty -echo changes the settings on the input file descriptor. If you're piping something to the stty command, then the input file descriptor is the pipe, and stty on a pipe is, eh, inappropriate (like the error message says).

It's unclear what you're trying to achieve. If you want to send the text test to your perl script to be read in the my $input = <STDIN>; line, then simply get rid of the stty stuff.

If you also want to read the text as user input (i.e. typed in) and while doing that prevent the text being echoed (e.g. a password) then test whether standard input is a tty (terminal) before doing the stty:

system( qw( stty -echo ) ) if -t 0;

That said, don't shell out for all sorts of things, that's not what perl is for (otherwise you might as well write the whole thing in shell). You can change stty settings from within perl, google is your friend.