Ruby input/output
From wikinotes
printing
puts (print with newline)
puts "hello"print (print w/o newline)
print "a", "b", 12printf
printf "num: %5.2f name: %s", 1.123, "alex" #> "num: 1.12 name: alex"
input
line = gets puts line
stdin/stdout/stderr
ARGF # stdin
file-like objects
fd = StringIO.new("a\nb\nc")
files
File.open('/var/tmp/file.txt', 'a') do |fd| fd.write("foo") end Dir.exist?('/directory') # directory exists File.exists?('/file.txt') # file exists