The particular characters that you need to escape are dependent upon the shell, not on perl. For the most part, you can just encase the perl string to be evaluated in single quotes in a unix shell, and make sure that you don't use single quotes in your perl. (I don't know about windows quoting) :

You can also use -l (that's a lower case L), so you can send a command quickly without the shell messing with it. (but again, this won't work in the times when you want the shell to do its magic, and it also keeps you from using the shell's abilities to repeat the command).

If there are times when you want to use shell variables in your line, you can either export them and reference them in perl as $ENV{"NAME"} rather than $NAME or you can end the quoting, use the variable, and then start it back up again:

perl -e 'print "you are logged in as $ENV{USER}\n";'
perl -e 'print "you are logged in as '$USER'\n";'
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The only thing that's really tricky is when you're trying to mix perl and shell commands ... which I'd advise not doing from the shell, as you can't always be sure of the output, and calling it from within perl.