while gets
if /Ruby/
print
end
end
##等同代码
ARGF.each {|line| print line if line =~ /Ruby/ }
##ARGF
##An object providing access to virtual concatenation of files passed as command-line
##arguments or standard input if there are no command-line arguments. A synonym for
##$<.
##等同代码
print ARGF.grep(/Ruby/)