你最喜欢在Bash中处理错误的方法是什么? 我在网上找到的处理错误的最好的例子是William Shotts, Jr在http://www.linuxcommand.org上写的。

他建议在Bash中使用以下函数进行错误处理:

#!/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."

在Bash脚本中是否有更好的错误处理例程?


当前回答

“set -e”的等效替代是

set -o errexit

它使标志的含义比“-e”更清晰。

随机添加:暂时禁用标志,并返回默认值(继续执行,不管退出码),只需使用

set +e
echo "commands run here returning non-zero exit codes will not cause the entire script to fail"
echo "false returns 1 as an exit code"
false
set -e

这排除了其他响应中提到的正确错误处理,但它是快速有效的(就像bash一样)。

其他回答

有时set -e, trap ERR,set -o,set -o pipefail和set -o errtrace不能正常工作,因为它们试图在shell中添加自动错误检测。这在实践中并不奏效。

在我看来,你应该编写自己的错误检查代码,而不是使用set -e和其他东西。如果您明智地使用set -e,请注意潜在的陷阱。

为了避免在运行代码时出现错误,您可以使用exec 1>/dev/null或exec 2>/dev/null Linux中的/dev/null是一个空设备文件。这将丢弃写入它的任何内容,并在读取时返回EOF。您可以在命令末尾使用此命令

对于try/catch,您可以使用&&或||来实现类似的行为 Use可以像这样使用&&

{ # try

    command &&
    # your command 

} || { 
    # catch exception 
}

或者你可以用if else:

if [[ Condition ]]; then
    # if true
else
    # if false
fi

$ ?显示最后一个命令的输出,它返回1或0

这个技巧对于缺少命令或函数非常有用。丢失的函数(或可执行文件)的名称将在$_中传递

function handle_error {
    status=$?
    last_call=$1

    # 127 is 'command not found'
    (( status != 127 )) && return

    echo "you tried to call $last_call"
    return
}

# Trap errors.
trap 'handle_error "$_"' ERR

我使用以下陷阱代码,它还允许通过管道和“时间”命令跟踪错误

#!/bin/bash
set -o pipefail  # trace ERR through pipes
set -o errtrace  # trace ERR through 'time command' and other functions
function error() {
    JOB="$0"              # job name
    LASTLINE="$1"         # line of error occurrence
    LASTERR="$2"          # error code
    echo "ERROR in ${JOB} : line ${LASTLINE} with exit code ${LASTERR}"
    exit 1
}
trap 'error ${LINENO} ${?}' ERR

不确定这是否对您有帮助,但我修改了这里的一些建议函数,以便在其中包括错误检查(先前命令的退出代码)。 在每次“检查”中,我还将错误的“消息”作为参数传递给日志记录。

#!/bin/bash

error_exit()
{
    if [ "$?" != "0" ]; then
        log.sh "$1"
        exit 1
    fi
}

现在要在同一个脚本中调用它(或者在另一个脚本中,如果我使用export -f error_exit),我只需写函数名并传递一个消息作为参数,如下所示:

#!/bin/bash

cd /home/myuser/afolder
error_exit "Unable to switch to folder"

rm *
error_exit "Unable to delete all files"

使用这个,我能够为一些自动化进程创建一个真正健壮的bash文件,它将在错误的情况下停止并通知我(log.sh将这样做)

我更喜欢简单的称呼。所以我用了一些看起来有点复杂,但很容易使用的东西。我通常只是复制并粘贴下面的代码到我的脚本。代码后面有解释。

#This function is used to cleanly exit any script. It does this displaying a
# given error message, and exiting with an error code.
function error_exit {
    echo
    echo "$@"
    exit 1
}
#Trap the killer signals so that we can exit with a good message.
trap "error_exit 'Received signal SIGHUP'" SIGHUP
trap "error_exit 'Received signal SIGINT'" SIGINT
trap "error_exit 'Received signal SIGTERM'" SIGTERM

#Alias the function so that it will print a message with the following format:
#prog-name(@line#): message
#We have to explicitly allow aliases, we do this because they make calling the
#function much easier (see example).
shopt -s expand_aliases
alias die='error_exit "Error ${0}(@`echo $(( $LINENO - 1 ))`):"'

I usually put a call to the cleanup function in side the error_exit function, but this varies from script to script so I left it out. The traps catch the common terminating signals and make sure everything gets cleaned up. The alias is what does the real magic. I like to check everything for failure. So in general I call programs in an "if !" type statement. By subtracting 1 from the line number the alias will tell me where the failure occurred. It is also dead simple to call, and pretty much idiot proof. Below is an example (just replace /bin/false with whatever you are going to call).

#This is an example useage, it will print out
#Error prog-name (@1): Who knew false is false.
if ! /bin/false ; then
    die "Who knew false is false."
fi