如何让 for 循环输出一次而不是每次迭代？

Question

我已经制作了这个简单的 bash 脚本来运行 ping 扫描并获取网络上活动的 MAC 地址，输出到一个文件，然后将该文件与一个文件，其中包含我从路由器中的 ARP table 中获取的已知 MAC 地址列表。

我怎样才能让 for 循环吐出一个输出，如“所有设备在您的网络上都很熟悉”，而不是为它迭代的每一行回显结果？

当前代码：

sudo nmap -sn 192.168.0.0/24 | grep "MAC" | awk '{print }'| sort > $HOME/Desktop/arp.txt

readarray -t mac <$HOME/Desktop/arptable.txt

for address in "${mac[@]}"; do
    if grep -Fxq "$address" $HOME/Desktop/arptable.txt;
    then 
        echo "$address is a known network device"
    else
        echo "WARNING: $address is an unknown device on the network"
    fi
done

我当前的输出如下：

XXXXXXXXXXXXXXXXX is a known network device
XXXXXXXXXXXXXXXXX is a known network device
XXXXXXXXXXXXXXXXX is a known network device
XXXXXXXXXXXXXXXXX is a known network device
XXXXXXXXXXXXXXXXX is a known network device
XXXXXXXXXXXXXXXXX is a known network device
XXXXXXXXXXXXXXXXX is a known network device
XXXXXXXXXXXXXXXXX is a known network device
XXXXXXXXXXXXXXXXX is a known network device
XXXXXXXXXXXXXXXXX is a known network device
XXXXXXXXXXXXXXXXX is a known network device
XXXXXXXXXXXXXXXXX is a known network device
XXXXXXXXXXXXXXXXX is a known network device
XXXXXXXXXXXXXXXXX is a known network device
XXXXXXXXXXXXXXXXX is a known network device
XXXXXXXXXXXXXXXXX is a known network device
XXXXXXXXXXXXXXXXX is a known network device
XXXXXXXXXXXXXXXXX is a known network device

免责声明：这只是一个项目，并未用作严肃的安全工具。

Answer 1

假设您仍想打印出 WARNING 消息...跟踪成功次数，如果等于数组中的条目数 mac[] 则打印您想要的消息，例如：

found=0

for address in "${mac[@]}"; do
    if grep -Fxq "$address" $HOME/Desktop/arptable.txt;
    then 
        ((found++))
    else
        echo "WARNING: $address is an unknown device on the network"
    fi
done 

[[ "${found}" -eq "${#max[@]}" ]] && echo "All Devices are familiar on your network"

或者，如果您生成任何 WARNING 消息，请清除标志：

foundall=true

for address in "${mac[@]}"; do
    if ! grep -Fxq "$address" $HOME/Desktop/arptable.txt;
    then 
        echo "WARNING: $address is an unknown device on the network"
        foundall=false
    fi
done 

[[ "${foundall}" == 'true' ]] && echo "All Devices are familiar on your network"

Answer 2

伪代码（我不会bash，不懂语法）：

sudo nmap -sn 192.168.0.0/24 | grep "MAC" | awk '{print }'| sort > $HOME/Desktop/arp.txt

readarray -t mac <$HOME/Desktop/arptable.txt

# everythingGood = true
for address in "${mac[@]}"; do
    if grep -Fxq "$address" $HOME/Desktop/arptable.txt;
    then 
    else
        # everythingGood = false
        # some code here maybe to store which ones failed
    fi
done 

# if everythingGood
    # echo "All Devices are familiar on your network"
# else
    # echo "WARNING: $address is an unknown device on the network"

如何让 for 循环输出一次而不是每次迭代？

How can I get a for loop to output once rather than every iteration?

bash

for-loop

nmap