Question

我想写这样的法典:

command="some command"

safeRunCommand $command

safeRunCommand() {
   cmnd=$1

   $($cmnd)

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

但是,这部法律并没有实现我的愿望。我在哪里犯错误?

Answer 1

固定代码如下:

#!/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,如果你看一下这一法典,我改变的几件事情是:

use of typeset is not necessary, but it is a good practice. It makes cmnd and ret_code local to safeRunCommand
use of ret_code is not necessary, but it is a good practice to store the 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 don’t 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 a command containing pipes can work fine

Note: Do remember some commands give 1 as the return code even though there isn t any error like grep. If grep found something it will return 0, else 1.

我用、KornShell 和 Bash 。该公司还从事罚款。让我知道,你是否面临这一问题。

Answer 2

提出

safeRunCommand() {
   "$@"

   if [ $? != 0 ]; then
      printf "Error when executing command:  $1 "
      exit $ERROR_CODE
   fi
}

Answer 3

应为<代码>$cmd,而不是$($cmd)。在我的盒子上,它做了一些细微的工作。

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

此外,当你必须打折你的印章时,用——x国旗执行。 [bash -x s.sh]。

Answer 4

你的文字有几个错误。

职能(附属机构)应在试图指定之前宣布。你可能希望(......)返回,但不要离开(......)你,让呼吁的团体检验某一指挥的成功或失败。除此以外,你没有抓住ERROR_ 因此,CODE一直为零(未界定)。

打破你可变的参考资料,同时用粗略的镜子,也是好的做法。您的法典不妨考虑:

#!/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} 
"
      exit ${ERROR_CODE}        #...consider  return()  here
   fi
}

safeRunCommand $command
command="cp"
safeRunCommand $command

Answer 5

通常的想法是管理指挥,然后使用<代码>$?,以获得撤离代码。然而,有时你有多种情况需要获得出境法。例如,你可能需要隐瞒其产出,但还是要退回,或印刷出勤守则和产出。

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

这将使你可以选择抑制你想要的撤离守则的指挥产出。当产出被抑制用于指挥时,撤离法将直接按职能归还。

我个人希望把这一职能放在我的 .bashrc。

下面我展示了你能够利用的几种方法:

# 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

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

您还应指出,您将看到的出勤代码为<编码>grep。指挥工作正在进行之中,这是最后一名指挥官被处决。 http://code>ls。

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