I always get confused by the difference between %x{}, backticks, and system
"command", so I wrote down what the difference was. %x{} is actually the
exact same thing as backticks, but it’s useful because you can nest backticks
inside it.
system "command" echoes to STDOUT, and returns true if the command succeeded.
irb > system "echo ABC"
ABC
=> true
Backticks and %x{ } do not echo to STDOUT, and return the result of
running the command.
irb > `echo ABC`
=> "ABC\n"
irb > %x{echo ABC}
=> "ABC\n"
irb > %x{echo `which ruby`}
=> "/Users/gabe/.rvm/rubies/ruby-1.9.2-p290/bin/ruby\n"