s = "naaaanbbbb"
s.sub!(/^n?/, "")

>> s = "naaaanbbbb" #=> "naaaanbbbb"
>> s.lstrip #=> "aaaanbbbb"

s = "naaaanbbbb"
s.strip!

str = "nmy string"
chomped_str = str.reverse.chomp.reverse

s.sub(/^[nr]*/, '')

"n  aaanbbb".reverse.chomp.reverse  # => "  aaanbbb"
"n  aaanbbb".lstrip                 # => "aaanbbb"

s.reverse.chomp.reverse

s = "naaaanbbbb"
s.slice!("n") # returns "n" but s also has the first newline removed.
puts s # shows s has the first newline removed