rake_run_external_command.rb

# Run external command and abort on failure
def shell(*cmd)
    return if cmd.empty?
    prog = cmd.first.to_s.split.first
    abort "#{prog}: command not found" if `which #{prog}`.empty?
    system *cmd
    abort "#{prog}: interrupted, signal #{$?.termsig}" if $?.signaled?
    abort "#{prog}: execution failed, exit code #{$?.exitstatus}" unless $?.success?
end

# Example of task using method shell()
task :test_shell do
    # print something
    shell "echo run command from a string"
    shell *%W{echo run command from an array, and preserve #{'s p  a   c    e     s'}}
    # can be interrupted with Ctrl-C
    shell 'sleep 10'
    # should fail with code 51
    shell *%W{sh -c #{"exit 51"}}
end