What did I miss?

If you use -E instead of -e, you can save yourself from typing use 5.012; :)

C:\test>perl -E "my $foo='abc def';my @foo=split m/ /,$foo; for (@foo)
+ {say $_}"
abc
def
[download]

A little more by omitting the $_:

C:\test>perl -E "my $foo='abc def';my @foo=split m/ /,$foo; for (@foo)
+ {say}"
abc
def
[download]

More still by using the modifier form of for:

C:\test>perl -E "my $foo='abc def';my @foo=split m/ /,$foo; say for @f
+oo"
abc
def
[download]

A lot more by using the string constant directly in the only place it is used:

C:\test>perl -E "my @foo=split m/ /,'abc def'; say for @foo"
abc
def
[download]

And finally, do away with the variables completely:

C:\test>perl -E "say for split m/ /,'abc def'"
abc
def
[download]