Question

有没有办法运行ruby脚本并在脚本中执行命令时仍然响应键击？

我想运行ruby脚本，但能够按“Space”并暂停脚本（在当前运行命令执行后），然后再次按“Space”并恢复脚本。

我唯一的想法（并且我确定它是一个奇怪的想法），是打开一个新线程并等待那里的击键，然后当生病时获得一个击键，设置一个stop_flag。只是现在看起来我需要在每个命令后检查这个标志以知道何时停止。

Answer 1

如果您在整个脚本中设置了适当的代码，则可以使用信号随意打开和关闭调试输出：

 pid = fork do

  # set up a logger
  require 'logger'
  log = Logger.new(STDOUT)
  log.level = Logger::INFO

  # toggle between INFO and DEBUG log levels on SIGUSR1
  trap(:SIGUSR1) do
    if log.level == Logger::DEBUG
      log.level = Logger::INFO
    else
      log.level = Logger::DEBUG
    end
  end

  # Main loop - increment a counter and occasionally print progress
  # as INFO level.  DEBUG level prints progress at every iteration.
  counter = 0
  loop do
    counter += 1
    exit if counter > 100
    log.debug "Counter is #{counter}"
    log.info "Counter is #{counter}" if counter % 10 == 0
    sleep 0.1
  end

end

# This makes sure that the signal sender process exits when the
# child process exits - only needed here to make the example
# terminate nicely.
trap(:SIGCLD) do
  exit(0) if Process.wait(-1, Process::WNOHANG) == pid
end

# This is an example of sending a signal to another process.
# Any process may signal another by pid.
# This example uses a forking parent-child model because this
# approach conveniently yields the child pid to the parent.
loop do
  puts "Press ENTER to send SIGUSR1 to child"
  STDIN.gets
  Process.kill :SIGUSR1, pid
end

forking和SIGCLD陷阱是使示例适合一个文件;任何过程都可能向另一个过程发送信号。

fork块中的代码是你的脚本。该脚本设置一个记录器，其默认日志级别为INFO，以及一个SIGUSR1信号处理程序，用于在DEBUG和INFO级别之间切换记录器。

fork块之外的东西只是向另一个进程发送信号的一个例子。按ENTER将发送信号并更改其他进程的日志记录级别。

这适用于POSIX系统，我不了解Windows。

Answer 2

与@Catnapper类似的想法，我以为我会分享它，虽然他打败了我。

require 'io/console' # Ruby 1.9

# Wait for the spacebar key to be pressed
def wait_for_spacebar
   sleep 1 while $stdin.getch != " "
end

# Fork a process that waits for the spacebar 
# to be pressed. When pressed, send a signal 
# to the main process.
def fork_new_waiter
   Process.fork do
      wait_for_spacebar
      Process.kill("USR1", Process.ppid)
   end
end

# Wait for a signal from the forked process
Signal.trap("USR1") do
   wait_for_spacebar

   # Debug code here

   fork_new_waiter
end

# Traps SIGINT so the program terminates nicely
Signal.trap("INT") do
   exit
end

fork_new_waiter

# Run program here in place of this loop
i = 0
loop do
   print i+=1
   sleep 1
end

Answer 3

您可以使用系统命令。

在Windows中使用：系统“暂停＆gt; null”

每个操作系统都有所不同。因此，您可以设置变量来检查操作系统。然后使用适当的命令。如果您想查看操作系统是否为Windows，您的代码将如下所示：

在ruby中运行脚本时等待按键

3 个答案: