You need to check the file out either unreserved or reserved. i.e. cleartool co [-unr] file

Then you can do with it what you will.

Not really sure how this is related to Perl, but uhmm...

perl -le '`cleartool co -unr file`'
[download]

for grins :) (code untested)

Oh and then simply chmod 644 (or, in Perl: chmod 0644) the file