我有一组在Red Hat系统上广泛使用的脚本函数。它们使用/etc/init.中的系统功能d/函数输出绿色[OK]和红色[FAILED]状态指示灯。

如果您想记录哪些命令失败，您可以选择将$LOG_STEPS变量设置为日志文件名。

使用

step "Installing XFS filesystem tools:"
try rpm -i xfsprogs-*.rpm
next

step "Configuring udev:"
try cp *.rules /etc/udev/rules.d
try udevtrigger
next

step "Adding rc.postsysinit hook:"
try cp rc.postsysinit /etc/rc.d/
try ln -s rc.d/rc.postsysinit /etc/rc.postsysinit
try echo $'\nexec /etc/rc.postsysinit' >> /etc/rc.sysinit
next

输出

Installing XFS filesystem tools:        [  OK  ]
Configuring udev:                       [FAILED]
Adding rc.postsysinit hook:             [  OK  ]

Code

#!/bin/bash

. /etc/init.d/functions

# Use step(), try(), and next() to perform a series of commands and print
# [  OK  ] or [FAILED] at the end. The step as a whole fails if any individual
# command fails.
#
# Example:
#     step "Remounting / and /boot as read-write:"
#     try mount -o remount,rw /
#     try mount -o remount,rw /boot
#     next
step() {
    echo -n "$@"

    STEP_OK=0
    [[ -w /tmp ]] && echo $STEP_OK > /tmp/step.$$
}

try() {
    # Check for `-b' argument to run command in the background.
    local BG=

    [[ $1 == -b ]] && { BG=1; shift; }
    [[ $1 == -- ]] && {       shift; }

    # Run the command.
    if [[ -z $BG ]]; then
        "$@"
    else
        "$@" &
    fi

    # Check if command failed and update $STEP_OK if so.
    local EXIT_CODE=$?

    if [[ $EXIT_CODE -ne 0 ]]; then
        STEP_OK=$EXIT_CODE
        [[ -w /tmp ]] && echo $STEP_OK > /tmp/step.$$

        if [[ -n $LOG_STEPS ]]; then
            local FILE=$(readlink -m "${BASH_SOURCE[1]}")
            local LINE=${BASH_LINENO[0]}

            echo "$FILE: line $LINE: Command \`$*' failed with exit code $EXIT_CODE." >> "$LOG_STEPS"
        fi
    fi

    return $EXIT_CODE
}

next() {
    [[ -f /tmp/step.$$ ]] && { STEP_OK=$(< /tmp/step.$$); rm -f /tmp/step.$$; }
    [[ $STEP_OK -eq 0 ]]  && echo_success || echo_failure
    echo

    return $STEP_OK
}

不要创建runner函数或使用set -e，而是使用trap:

trap 'echo "error"; do_cleanup failed; exit' ERR
trap 'echo "received signal to stop"; do_cleanup interrupted; exit' SIGQUIT SIGTERM SIGINT

do_cleanup () { rm tempfile; echo "$1 $(date)" >> script_log; }

command1
command2
command3

该trap甚至可以访问触发它的命令的行号和命令行。变量为$BASH_LINENO和$BASH_COMMAND。

你说的“退出并回复错误”是什么意思?如果您的意思是希望脚本在任何命令失败时立即终止，那么就这样做

set -e    # DON'T do this.  See commentary below.

在脚本的开头(但注意下面的警告)。不要回显错误消息:让失败的命令处理它。换句话说，如果你这样做:

#!/bin/sh

set -e    # Use caution.  eg, don't do this
command1
command2
command3

而command2失败，同时打印一个错误消息到stderr，那么似乎您已经实现了您想要的。(除非我误解了你想要的!)

因此，您编写的任何命令都必须表现良好:它必须向stderr而不是stdout报告错误(问题中的示例代码将错误输出到stdout)，并且在失败时必须以非零状态退出。

However, I no longer consider this to be a good practice. set -e has changed its semantics with different versions of bash, and although it works fine for a simple script, there are so many edge cases that it is essentially unusable. (Consider things like: set -e; foo() { false; echo should not print; } ; foo && echo ok The semantics here are somewhat reasonable, but if you refactor code into a function that relied on the option setting to terminate early, you can easily get bitten.) IMO it is better to write:

 #!/bin/sh

 command1 || exit
 command2 || exit
 command3 || exit

or

#!/bin/sh

command1 && command2 && command3

就我个人而言，我更喜欢使用轻量级方法，如下所示;

yell() { echo "$0: $*" >&2; }
die() { yell "$*"; exit 111; }
try() { "$@" || die "cannot $*"; }
asuser() { sudo su - "$1" -c "${*:2}"; }

使用示例:

try apt-fast upgrade -y
try asuser vagrant "echo 'uname -a' >> ~/.profile"

另一种方法是简单地将命令与&&连接在一起，这样第一个失败的命令就会阻止其他命令的执行:

command1 &&
  command2 &&
  command3

这不是您在问题中要求的语法，但它是您所描述的用例的通用模式。一般来说，这些命令应该负责打印失败，这样您就不必手动执行了(当您不想要错误时，可以使用-q标志来屏蔽错误)。如果您有修改这些命令的能力，我会将它们编辑为在失败时大喊，而不是将它们包装在具有这种功能的其他东西中。

还要注意，你不需要这样做:

command1
if [ $? -ne 0 ]; then

你可以简单地说:

if ! command1; then

当你确实需要检查返回码时，使用算术上下文而不是[…]- ne:

ret=$?
# do something
if (( ret != 0 )); then

不管怎样，编写代码来检查每个命令是否成功的更简单的方法是:

command1 || echo "command1 borked it"
command2 || echo "command2 borked it"

它仍然很乏味，但至少是可读的。