使用bash实现控制任务并发数的功能

#!/bin/bash#CMDS[1]="echo $USER' 01 BEGIN' && sleep 6 && echo $USER' 01 END'"CMDS[2]="echo $USER' 02 BEGIN' && sleep 3 && echo $USER' 02 END'"CMDS[3]="echo $USER' 03 BEGIN' && sleep 7 && echo $USER' 03 END'"CMDS[4]="echo $USER' 04 BEGIN' && sleep 4 && echo $USER' 04 END'"CMDS[5]="echo $USER' 05 BEGIN' && sleep 2 && echo $USER' 05 END'"CMDS[6]="echo $USER' 06 BEGIN' && sleep 5 && echo $USER' 06 END'"N=${#CMDS[@]}MAX=3PIDS=''for I in $(seq $N)do    while [ 1 -gt 0 ]    do        C=0        pids=''        for PID in $PIDS        do            ps $PID >/dev/null 2>/dev/null            if [ $? -eq 0 ]            then                pids="$pids $PID"                (( C = C + 1 ))            fi        done        PIDS=$pids        [ $C -lt $MAX ] && break        sleep 1    done    #echo $i ${CMDS[$i]}    CMD=${CMDS[$I]}    bash -c "$CMD" &    PIDS="$PIDS $!"donewait