A readline + -e oddity: readline opens files even with -e --- need "readline STDIN" to read from console

[cxw]

(This is my first meditation. I am posting in hopes it will help someone down the line! I can't find another node about this, but that doesn't mean there isn't one :) .)

I needed to run a program and then wait for the user to hit Enter. I tried this:

$ perl -e 'system(@ARGV); readline' echo foo
foo
Can't open echo: No such file or directory at -e line 1.
Can't open foo: No such file or directory at -e line 1.

Not what I expected!

After all, perlrun says that:

If -e is given, Perl will not look for a filename in the argument list.

What I was missing is that readline does look at the argument list. Readline:

reads ...from *ARGV if EXPR is not provided

So what I needed was to expressly read from STDIN to get my keypress:

                                 # vvvvv
$ perl -e 'system(@ARGV); readline STDIN' echo foo
foo
    (<=== waited here for me to press Enter)