What does *$< mean in Ruby?

Question

I was analyzing my friend's code, and I saw this little snippet:

n,a=*$<

I can't figure out what it means - I've searched on many sites, but they don't seem to recognize the special characters.

Answer 1

$< is ARGF. From ruby's standard docummentation:

ARGF is a stream designed for use in scripts that process files given as command-line arguments or passed in via STDIN.

A super good explanation here

* is splat operator.

You are assigning to a and n what's inside ARGF/STDIN at that point.

Example:

raducroitoru@dotix ~$ cat a.txt                                         
a
b
c

raducroitoru@dotix ~$ cat a.rb                                          
a, n = *$<
puts "a is: #{a}"
puts "n is: #{n}"

raducroitoru@dotix ~$ ruby a.rb a.txt                                   
a is: a
n is: b