# bash and sh
[jeffa@trinity perl]$ perl -ple "}{$_=$." foo.pl
Can't modify constant item in scalar assignment ...

# csh and tcsh
[jeffa@trinity ~/perl]$ perl -ple "}{$_=$." foo.pl
Illegal variable name.

# ksh
$ perl -ple "}{$_=$." foo.pl
Bareword found where operator expected ...

##</code><code>##

perl -ple "}{*_=*." foo.pl