>perl -wMstrict -le
"print 4 + 'a';
 ;;
 use warnings FATAL => 'numeric';
 print 5 + 'b';
"
Argument "a" isn't numeric in addition (+) at -e line 1.
4
Argument "b" isn't numeric in addition (+) at -e line 1.

>perl -wMstrict -le
"print 4 + 'a';
 ;;
 use warnings FATAL => 'all';
 print 5 + 'b';
"
Argument "a" isn't numeric in addition (+) at -e line 1.
4
Argument "b" isn't numeric in addition (+) at -e line 1.