相关疑难解决方法(0)

如何重试bash命令直到状态正常或达到超时？

我最好的镜头(我正在寻找更简单的东西):

NEXT_WAIT_TIME=0
COMMAND_STATUS=1
until [ $COMMAND_STATUS -eq 0 || $NEXT_WAIT_TIME -eq 4 ]; do
  command
  COMMAND_STATUS=$?
  sleep $NEXT_WAIT_TIME
  let NEXT_WAIT_TIME=NEXT_WAIT_TIME+1
done

我编写了一个运行命令的函数,它以两个args为第一个命令,以秒为单位的第二个超时:

#! /bin/bash

function run_cmd {
    cmd="$1"; timeout="$2"
    grep -qP "^\d+$" <<< "$timeout" || timeout=10

    stderrfile=$(readlink /proc/$$/fd/2)
    exec 2<&-

    exitfile=/tmp/exit_$(date +%s.%N)
    (eval "$cmd";echo $? > $exitfile) &

    start=$(date +%s)
    while true; do
        pid=$(jobs -l | awk '/Running/{print $2}')
        if [ -n "$pid" ]; then
            now=$(date +%s)
            running=$(($now - $start))
            if [ "$running" -ge "$timeout" ];then
                kill -15 "$pid"
                exit=1
            fi
            sleep 1
        else
            break
        fi

    done 
    test -n "$exit" || exit=$(cat $exitfile)
    rm $exitfile
    exec 2>$stderrfile              
    return "$exit"
}


function …

对于执行存储在变量中的eval命令,使用命令:

???> a="echo -e 'a\nb' | wc -l"
???> eval $a
2

但它如何与timeout命令结合？我试过以下哪个给了我错误的输出:

???> timeout 10 $a
'a
b' | wc -l

以下给出了我的错误:

???> timeout 10 "$a"
timeout: failed to run command `echo -e \'a\\nb\' | wc -l': No such file or directory

???> timeout 10 $(eval $a)
timeout: failed to run command `2': No such file or directory

???> timeout 10 $(eval "$a")
timeout: failed to run command `2': No such file or directory

问题还可以解决:我怎样才能确定以下命令是否正确执行？ …