在Bash中处理错误 [英] Error handling in Bash

问题描述

你最喜欢的方法是什么来处理Bash中的错误？
在网页上找到的错误处理最好的例子是William Shotts，Jr在 http：// www .linuxcommand.org 。他建议在Bash中使用以下函数进行错误处理：

 ＃＃/ bin / bash 
 
＃一个slicker错误处理例程
 
＃我在我的脚本中放了一个名为PROGNAME的变量，
＃程序正在运行。您可以从命令行（$ 0）的第一个项目获取
＃的值。 
 
＃参考：这是从< http：//www.linuxcommand.org/wss0150.php> 
 
 PROGNAME = $（basename $ 0）
 
函数error_exit 
 {
 
＃----------- -------------------------------------------------- --- 
＃由于致命程序错误而退出的功能
＃接受1个参数：
包含描述性错误消息的字符串
＃---------- -------------------------------------------------- ---- 
 
 echo$ {PROGNAME}：$ {1： - 未知错误}1& 2 
退出1 
} 
 
＃示例调用error_exit函数。注意包含
＃的LINENO环境变量。它包含当前的
＃行号。 
 
 echo行号和消息
 error_exit的错误示例$ LINENO：发生错误。 
  

您是否在Bash脚本中使用了更好的错误处理例程？

解决方案

使用陷阱

  tempfiles = ）
 cleanup（）{
 rm -f$ {tempfiles [@]}
} 
陷阱清理0 
 
错误（）{
本地parent_lineno =$ 1
本地消息=$ 2
本地代码=$ {3：-1}
如果[[-n$ message]] ;然后
 echo错误在$ {parent_lineno}上或附近：$ {message};退出状态$ {code}
 else 
 echo错误在或附近$ {parent_lineno} ;退出状态$ {code}
 fi 
退出$ {code}
} 
陷阱'错误$ {LINENO}'ERR 
  

...然后，每当您创建一个临时文件：

  temp_foo =$（mktemp -t foobar.XXXXXX）
 tempfiles + =（$ temp_foo）
  

和 $ temp_foo 将在退出时删除，并打印当前行号。 （ set -e 同样会给你错误的退出行为，并削弱了代码的可预测性和可移植性。）

您可以让陷阱调用错误（在这种情况下，它使用默认退出代码1，没有消息）或自己调用并提供显式值;例如：

 错误$ {LINENO}foobar failed2 
  / pre> 
 
 
将退出状态2，并给出明确的消息。
 
What is your favorite method to handle errors in Bash? 
The best example of handling errors I have found on the web was written by William Shotts, Jr at http://www.linuxcommand.org. 

He suggests using the following function for error handling in Bash:
#!/bin/bash

# A slicker error handling routine

# I put a variable in my scripts named PROGNAME which
# holds the name of the program being run.  You can get this
# value from the first item on the command line ($0).

# Reference: This was copied from <http://www.linuxcommand.org/wss0150.php>

PROGNAME=$(basename $0)

function error_exit
{

#   ----------------------------------------------------------------
#   Function for exit due to fatal program error
#       Accepts 1 argument:
#           string containing descriptive error message
#   ---------------------------------------------------------------- 

    echo "${PROGNAME}: ${1:-"Unknown Error"}" 1>&2
    exit 1
}

# Example call of the error_exit function.  Note the inclusion
# of the LINENO environment variable.  It contains the current
# line number.

echo "Example of error with line number and message"
error_exit "$LINENO: An error has occurred."
Do you have a better error handling routine that you use in Bash scripts?
解决方案
Use a trap!
tempfiles=( )
cleanup() {
  rm -f "${tempfiles[@]}"
}
trap cleanup 0

error() {
  local parent_lineno="$1"
  local message="$2"
  local code="${3:-1}"
  if [[ -n "$message" ]] ; then
    echo "Error on or near line ${parent_lineno}: ${message}; exiting with status ${code}"
  else
    echo "Error on or near line ${parent_lineno}; exiting with status ${code}"
  fi
  exit "${code}"
}
trap 'error ${LINENO}' ERR
...then, whenever you create a temporary file:
temp_foo="$(mktemp -t foobar.XXXXXX)"
tempfiles+=( "$temp_foo" )
and $temp_foo will be deleted on exit, and the current line number will be printed. (set -e will likewise give you exit-on-error behavior, though it comes with serious caveats and weakens code's predictability and portability).

You can either let the trap call error for you (in which case it uses the default exit code of 1 and no message) or call it yourself and provide explicit values; for instance:
error ${LINENO} "the foobar failed" 2
will exit with status 2, and give an explicit message.

                        
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