Perl: The Difference Between My and Local Variables

Cited from The difference between my and local

'local' temporarily changes the value of the variable, but only within the scope it exists in.

'my' creates a variable that does not appear in the symbol table, and does not exist outside of the scope that it appears in.

$::a refers to $a in the 'global' namespace.

use local when:

• you want to amend a special Perl variable, eg $/ when reading in a file. my $/; throws a compile-time error