在 bash/ksh 中获取命令的退出代码

Get exit code for command in bash/ksh

提问by Kolesar

I want to write code like this:

我想写这样的代码：

command="some command"

safeRunCommand $command

safeRunCommand() {
   cmnd=

   $($cmnd)

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

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

但是这段代码没有按照我想要的方式工作。我哪里出错了？

回答by havexz

Below is the fixed code:

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"

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

现在，如果您查看此代码，我更改的几件事是：

• use of typesetis not necessary but a good practice. It make cmndand ret_codelocal to safeRunCommand
• use of ret_codeis 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 cmndwill get only the value lsand 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

• 使用typeset不是必需的，而是一种很好的做法。它使cmnd和ret_code本地safeRunCommand
• 使用 ofret_code不是必需的，而是将返回代码存储在某个变量中（并尽快存储）的好做法，以便您可以像我在后面那样使用它printf "Error : [%d] when executing command: '$command'" $ret_code
• 传递带有引号的命令，例如safeRunCommand "$command". 如果你不这样做，那么cmnd只会得到价值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typeset cmnd="$*"，typeset cmnd="$1"则可以使用代替。您可以根据命令参数的复杂程度来尝试两者。
• eval 用于评估，以便包含管道的命令可以正常工作

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

注意：请记住，即使没有像grep. 如果grep找到一些东西，它将返回 0 否则返回 1。

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

我已经用 KSH/BASH 测试过。它工作得很好。如果您在运行此程序时遇到问题，请告诉我。

回答by sehe

Try

尝试

safeRunCommand() {
   "$@"

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

回答by Priyank Bhatnagar

It should be $cmdinstead of $($cmd). Works fine with that on my box.

它应该$cmd代替$($cmd). 在我的盒子上很好用。

Edit:Your script works only for one-word commands, like ls. It will not work for "ls cpp". For this to work, replace cmd="$1"; $cmdwith "$@". And, do not run your script as command="some cmd"; safeRun command, run it as safeRun some cmd.

编辑：您的脚本仅适用于单字命令，例如 ls。它不适用于“ls cpp”。为此，请替换cmd="$1"; $cmd为"$@". 并且，不要将脚本作为command="some cmd"; safeRun command运行，而是作为safeRun some cmd.

Also, when you have to debug your bash scripts, execute with '-x' flag. [bash -x s.sh].

此外，当您必须调试 bash 脚本时，请使用“-x”标志执行。[bash -x s.sh]。

回答by JRFerguson

There are several things wrong with your script.

您的脚本有几处错误。

Functions (subroutines) should be declared before attempting to call them. You probably want to return() but not exit() from your subroutine to allow the calling block to test the success or failure of a particular command. That aside, you don't capture 'ERROR_CODE' so that is always zero (undefined).

函数（子程序）应该在尝试调用它们之前声明。您可能希望从子例程中返回（）而不是退出（），以允许调用块测试特定命令的成功或失败。除此之外，您不会捕获“ERROR_CODE”，因此它始终为零（未定义）。

It's good practice to surround your variable references with curly braces, too. Your code might look like:

用大括号将变量引用括起来也是一种很好的做法。您的代码可能如下所示：

#!/bin/sh
command="/bin/date -u"          #...Example Only

safeRunCommand() {
   cmnd="$@"                    #...insure whitespace passed and preserved
   $cmnd
   ERROR_CODE=$?                #...so we have it for the command we want
   if [ ${ERROR_CODE} != 0 ]; then
      printf "Error when executing command: '${command}'\n"
      exit ${ERROR_CODE}        #...consider 'return()' here
   fi
}

safeRunCommand $command
command="cp"
safeRunCommand $command

回答by Nathan F.

The normal idea would be to run the command and then use $?to get the exit code. However, some times you have multiple cases in which you need to get the exit code. For example, you might need to hide it's output but still return the exit code, or print both the exit code and the output.

通常的想法是运行该命令，然后使用它$?来获取退出代码。但是，有时您有多种情况需要获取退出代码。例如，您可能需要隐藏它的输出但仍返回退出代码，或者同时打印退出代码和输出。

ec() { [[ "" == "-h" ]] && { shift && eval $* > /dev/null 2>&1; ec=$?; echo $ec; } || eval $*; ec=$?; }

This will give you the option to suppress the output of the command you want the exit code for. When the output is suppressed for the command, the exit code will directly be returned by the function.

这将使您可以选择抑制想要退出代码的命令的输出。当命令的输出被抑制时，退出代码将直接由函数返回。

I personally like to put this function in my .bashrcfile

我个人喜欢把这个函数放在我的.bashrc文件中

Below I demonstrate a few ways in which you can use this:

下面我演示了几种可以使用它的方法：

---

---

# In this example, the output for the command will be
# normally displayed, and the exit code will be stored
# in the variable $ec.

$ ec echo test
test
$ echo $ec
0

---

---

# In this example, the exit code is output
# and the output of the command passed
# to the `ec` function is suppressed.

$ echo "Exit Code: $(ec -h echo test)"
Exit Code: 0

---

---

# In this example, the output of the command
# passed to the `ec` function is suppressed
# and the exit code is stored in `$ec`

$ ec -h echo test
$ echo $ec
0

---

---

Solution to your code using this function

使用此函数解决您的代码

#!/bin/bash
if [[ "$(ec -h 'ls -l | grep p')" != "0" ]]; then
    echo "Error when executing command: 'grep p' [$ec]"
    exit $ec;
fi

You should also note that the exit code you will be seeing will be for the grepcommand that's being run, as it is the last command being executed. Not the ls.

您还应该注意，您将看到的退出代码将用于grep正在运行的命令，因为它是正在执行的最后一个命令。不是ls.