Sure...

tetsujin  13> /usr/bin/head -3 /usr/bin/perldoc
#!/usr/bin/perl
    eval 'exec /usr/bin/perl -S $0 ${1+"$@"}'
        if 0;
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perldoc, oddly enough, is written in perl, and uses /usr/bin/perl to run itself. So when perl itself has issues, so does perldoc. Many of the additional tools that come with perl are written in perl, such as s2p. You can look through these to see some of Larry and Tom's coding styles, as well as Other Ways To Do It.