对于多个命令，是否有类似于pipefail的东西，比如'try'语句，但在bash中。我想这样做:
echo "trying stuff"
try {
command1
command2
command3
}
在任何时候，如果任何命令失败了，就退出并回显该命令的错误。我不想做这样的事情:
command1
if [ $? -ne 0 ]; then
echo "command1 borked it"
fi
command2
if [ $? -ne 0 ]; then
echo "command2 borked it"
fi
等等……或者类似的事情:
pipefail -o
command1 "arg1" "arg2" | command2 "arg1" "arg2" | command3
因为我相信每个命令的参数(如果我错了请纠正我)会相互干扰。这两种方法对我来说似乎非常冗长和讨厌，所以我在这里呼吁一种更有效的方法。
当前回答
对不起，我不能对第一个答案发表评论 但是你应该使用新实例来执行命令:
#!/bin/bash
function check_exit {
cmd_output=$($@)
local status=$?
echo $status
if [ $status -ne 0 ]; then
echo "error with $1" >&2
fi
return $status
}
function run_command() {
exit 1
}
check_exit run_command
其他回答
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
当我使用ssh时，我需要在errexit (set -e)模式下区分由连接问题和远程命令的错误代码引起的问题。我使用以下函数:
# prepare environment on calling site:
rssh="ssh -o ConnectionTimeout=5 -l root $remote_ip"
function exit255 {
local flags=$-
set +e
"$@"
local status=$?
set -$flags
if [[ $status == 255 ]]
then
exit 255
else
return $status
fi
}
export -f exit255
# callee:
set -e
set -o pipefail
[[ $rssh ]]
[[ $remote_ip ]]
[[ $( type -t exit255 ) == "function" ]]
rjournaldir="/var/log/journal"
if exit255 $rssh "[[ ! -d '$rjournaldir/' ]]"
then
$rssh "mkdir '$rjournaldir/'"
fi
rconf="/etc/systemd/journald.conf"
if [[ $( $rssh "grep '#Storage=auto' '$rconf'" ) ]]
then
$rssh "sed -i 's/#Storage=auto/Storage=persistent/' '$rconf'"
fi
$rssh systemctl reenable systemd-journald.service
$rssh systemctl is-enabled systemd-journald.service
$rssh systemctl restart systemd-journald.service
sleep 1
$rssh systemctl status systemd-journald.service
$rssh systemctl is-active systemd-journald.service
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。
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$BASH_COMMAND。
对于无意中发现这条线索的鱼壳用户。
假设foo是一个不“返回”(回显)值的函数，但它像往常一样设置退出码。 为了避免在调用函数后检查$status，你可以这样做:
foo; and echo success; or echo failure
如果它太长，不能放在一行上:
foo; and begin
echo success
end; or begin
echo failure
end
