救援“未找到命令"；对于IO :: popen [英] Rescuing "command not found" for IO::popen

问题描述

当我将IO::popen与不存在的命令一起使用时，我会在屏幕上看到一条错误消息:

When I use IO::popen with a non-existent command, I get an error message printed to the screen:

 irb> IO.popen "fakefake"
  #=> #<IO:0x187dec>
 irb> (irb):1: command not found: fakefake

有什么办法可以捕获此错误，以便可以从脚本中进行检查?

Is there any way I can capture this error, so I can examine from within my script?

推荐答案

是:升级到ruby 1.9.如果在1.9中运行该命令，则会引发Errno::ENOENT，并且可以rescue.

Yes: Upgrade to ruby 1.9. If you run that in 1.9, an Errno::ENOENT will be raised instead, and you will be able to rescue it.

(编辑)这是在1.8版中做的一种怪异的方式:

(Edit) Here is a hackish way of doing it in 1.8:

error = IO.pipe
$stderr.reopen error[1]
pipe = IO.popen 'qwe' # <- not a real command
$stderr.reopen IO.new(2)
error[1].close

if !select([error[0]], nil, nil, 0.1)
  # The command was found. Use `pipe' here.
  puts 'found'
else
  # The command could not be found.
  puts 'not found'
end

这篇关于救援“未找到命令"；对于IO :: popen的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！