Bash 内循环赢得'；不要打断

代码可以工作，但不会继续运行卡在内部循环中的循环不确定问题出在哪里，或者端口扫描可能需要很多时间

#!/bin/bash

up()
{
  ping -c 1 $1 > /dev/null
  [ $? -eq 0 ] && echo IP: $i is up.
}

for i in 192.168.0.{1..255} 
do
up $i & disown
    for port in {1..100};do
    2>/dev/null echo > /dev/tcp/$i/$port
    if [ $? == 0 ]
            then
                    {
                    echo "port $port is open"
                    continue
                    }
    fi
    done
done
exit

在bash中扫描Ping+TCP 为了保持礼貌，我尝试将脚本限制为8182个分叉

此脚本扫描

/etc/services

，然后可以扫描所有（所需）端口。（见评论）

完整扫描我复杂的专用子网需要5分钟以上才能完成（扫描255台主机上的303个端口，发现27个以上）

---

您正在使用分配给基本服务的端口，这很可能会把事情搞砸。执行

less/etc/services

并查看您尝试使用的保留端口。这可能会有帮助：

#!/bin/bash
BaseIP=${1:-192.168.1}
ports=(21 22 25 80 443 9100)
# ports=({1..100})              # Uncomment this for ports 1-100

while IFS=$' \t\r\n/' read serv port prot comm ;do
 [ "$prot" = "tcp" ] && printf -v $prot[$port] %s "$serv"
done </etc/services
# ports=(${!tcp[@]})            # Uncomment this for all known ports

isup() { ping -W 1 -c1 -n $1 &>/dev/null && printf "IP: %-17sis up.\n" $1;}

tstport() { local _tst _prot=${3:-tcp}; local -n _var=$_prot[$2]
    {
        exec {_tst}<>/dev/$_prot/$1/$2 && exec {_tst}<&- &&
            printf "IP: %-16s port %6d open (%s)\n" $1 $2 ${_var:-unassigned}
    } 2>/dev/null
}
step=$((8180/(${#ports[@]}+1)))
for ((i=1;i < 255;i+=step)) {
        max=$((i+step>255?255:i+step))
        for ((l=i;l<max;l++)) {
                isup $BaseIP.$l &
                exec {dummy}< <(:)
                for port in ${ports[@]} ;do
                    exec {dummy2}< <(:)
                    tstport $BaseIP.$l $port & read -u $dummy2 -t .02
                    exec {dummy2}<&-
                done &
                read -u $dummy -t .02
                exec {dummy}<&-
            } |
                sed -une /./p
    }

IP: 192.168.1.1      is up.
IP: 192.168.1.3      is up.
IP: 192.168.1.3      port     22 open (ssh)
IP: 192.168.1.15     is up.
IP: 192.168.1.15     port     22 open (ssh)
IP: 192.168.1.15     port    139 open (netbios-ssn)
IP: 192.168.1.15     port    445 open (microsoft-ds)
IP: 192.168.1.15     port    515 open (printer)
IP: 192.168.1.39     is up.
IP: 192.168.1.39     port     22 open (ssh)