获取bash/ksh中命令的退出代码 [英] Get exit code for command in bash/ksh

问题描述

我要编写这样的代码:

command="some command"

safeRunCommand $command

safeRunCommand() {
   cmnd=$1

   $($cmnd)

   if [ $? != 0 ]; then
      printf "Error when executing command: '$command'"
      exit $ERROR_CODE
   fi
}

但是此代码无法按照我想要的方式工作. 我在哪里弄错了?

But this code does not working the way I want. Where I made mistake?

推荐答案

下面是固定代码:

#!/bin/ksh
safeRunCommand() {
  typeset cmnd="$*"
  typeset ret_code

  echo cmnd=$cmnd
  eval $cmnd
  ret_code=$?
  if [ $ret_code != 0 ]; then
    printf "Error : [%d] when executing command: '$cmnd'" $ret_code
    exit $ret_code
  fi
}

command="ls -l | grep p"
safeRunCommand "$command"

现在，如果您看一下这段代码，我需要更改的几件事是:

Now if you look into this code few things that I changed are:

• typeset的使用不是必需的，而是一种很好的做法.它将cmnd和ret_code本地化为safeRunCommand
• 没有必要使用ret_code，但这是将返回码存储在某个变量中(并尽快存储)的一种好习惯，这样您以后就可以像在printf "Error : [%d] when executing command: '$command'" $ret_code
中那样使用它了.
• 传递命令，并用引号引起来，例如safeRunCommand "$command".如果您不这样做，那么cmnd将仅获得值ls而不是ls -l.如果您的命令包含管道，则更为重要.
• 如果要保留空格，可以使用typeset cmnd="$*"代替typeset cmnd="$1".您可以尝试两种方法，具体取决于命令参数的复杂程度.
• 使用eval进行评估，以便包含管道的命令可以正常工作

• use of typeset is not necessary but a good practice. It make cmnd and ret_code local to safeRunCommand
• use of ret_code is not necessary but a good practice to store return code in some variable (and store it ASAP) so that you can use it later like I did in printf "Error : [%d] when executing command: '$command'" $ret_code
• pass the command with quotes surrounding the command like safeRunCommand "$command". If you dont then cmnd will get only the value ls and not ls -l. And it is even more important if your command contains pipes.
• you can use typeset cmnd="$*" instead of typeset cmnd="$1" if you want to keep the spaces. You can try with both depending upon how complex is your command argument.
• eval is used to evaluate so that command containing pipes can work fine

注意:即使没有像grep这样的错误，也请记住某些命令将1作为返回码.如果grep找到了某些内容，它将返回0，否则返回1.

NOTE: Do remember some commands give 1 as return code even though there is no error like grep. If grep found something it will return 0 else 1.

我已经用KSH/BASH进行了测试.而且效果很好.让我知道您是否遇到运行此问题.

I had tested with KSH/BASH. And it worked fine. Let me know if u face issues running this.

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