$ /usr/bin/perl       -e 'open my $fh, "uname -rs |"; print <$fh>;'
Can't use an undefined value as filehandle reference at -e line 1.

##</code><code>##

$ /usr/local/bin/perl -e 'open my $fh, "uname -rs |"; print <$fh>;'
SunOS 5.8