From the friendly documentation:

"The strict pragma disables certain Perl expressions that could behave unexpectedly or are difficult to debug, turning them into errors. The effect of this pragma is limited to the current file or scope block. If no import list is supplied, all possible restrictions are assumed. (This is the safest mode to operate in, but is sometimes too strict for casual programming.) Currently, there are three possible things to be strict about: "subs", "vars", and "refs"."

"The warnings pragma gives control over which warnings are enabled in which parts of a Perl program. It's a more flexible alternative for both the command line flag -w and the equivalent Perl variable, $^W . This pragma works just like the strict pragma. This means that the scope of the warning pragma is limited to the enclosing block. It also means that the pragma setting will not leak across files (via use, require or do). This allows authors to independently define the degree of warning checks that will be applied to their module. By default, optional warnings are disabled, so any legacy code that doesn't attempt to control the warnings will work unchanged."

See strict and warnings and Why use strict and warnings?.

Regards, Karl