Section: Perl Programmers Reference Guide (3pm)
ops - Perl pragma to restrict unsafe operations when compiling
perl -Mops=:default ... # only allow reasonably safe operations
perl -M-ops=system ... # disable the 'system' opcode
Since the "ops"
pragma currently has an irreversible global effect, it is
only of significant practical use with the "-M"
option on the command line.
See the Opcode module for information about opcodes, optags, opmasks
and important information about safety.
Opcode, Safe, perlrun