What is the difference between \1 and $1 in a Perl regex?

Question

What is the difference of doing \\1 as opposed to $1 if any, or are they interchangeable in all situations.

Example:

s/([a-z]+),afklol/$1,bck/;
#agai         


        

Answer 1

They give the same result, but $1 retains its value while \1 does not. Try this:

s/([a-z]+),afklol/$1,bck/;
print "\$1 is $1\n";
#against
s/([a-z]+),afklol/\1,bck/;
print "\\1 is \1\n";