The "proper" way to do this, from the bash-scripting presepective, is probably to use exit() so that you my test the exit status just as you would with other commands:

$ a=foo b=bar; export a b; perl -le 'exists $ENV{a} && exists $ENV{b} 
+? exit 0 : exit 1' && echo 'success'
success
[download]

You can also find the exit status in the shell's $? variable:

$ a=foo b=bar; export a b; perl -le 'exists $ENV{a} && exists $ENV{b} 
+? exit 0 : exit 1'; echo "exit status: $?"
exit status: 0
[download]

conv

Comment on Re: exchanging data between shell script and perl -e Select or Download Code