OK, let's take the classic root crontab code:

find /tmp /usr/tmp -atime +7 -print | xargs /bin/rm -f
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And then I come along (as an ordinary user) and do the following:

$ mkdir -p "/tmp/foo
/etc" # yes, that's a newline after foo before the /etc
$ touch "/tmp/foo
/etc/passwd" # yes, that's a newline after foo again
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And then sit back 7 days. Boom. You have no /etc/passwd.

The problem is that you are using newline as a delimiter, and yet it is a legal filename character. You need find .. -print0 and xargs with a -0, but that's not portable. Even though Perl isn't strictly everywhere, it's everywhere the perlmonks are, so my solution succeeds in a safe way.

-- Randal L. Schwartz, Perl hacker