perl -e'%hash=(1,"a",2,"b",3,"c"); foreach keys ( %hash ) { print }'

Missing $ on loop variable at -e line 1.

perl -e'%hash=(1,"a",2,"b",3,"c"); foreach  ( %hash ) { print }'

1a3c2b

perl -e'%hash=(1,"a",2,"b",3,"c"); foreach $keys ( %hash ) { print $keys }'

1a3c2b

 perl -e'%hash=(1,"a",2,"b",3,"c"); foreach ( keys %hash) { print }'

132