Prepend a single line to file with Ruby

Question

I\'d like to add a single line to the top a of file with Ruby like this:

# initial file contents
something
else

# file contents after prepending \"hello\" o         


        

Answer 1

fwiw this seems to work:

#!usr/bin/ruby

f = File.open("myfile", "r+")
lines = f.readlines
f.close

lines = ["something\n"] + lines

output = File.new("myfile", "w")
lines.each { |line| output.write line }
output.close