If you want to affect the environment of your process or your child processes, just use the %ENV
hash:
$ENV{CVSROOT}='<cvs>';
If you want to affect the environment of your parent process, you can't. At least not without cooperation of the parent process. The standard process is to emit a shell script and have the parent process execute that shell script:
#!/usr/bin/perl -w
print 'export CVSROOT=<cvs>';
... and call that script from the shell (script) as:
eval `myscript.pl`
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