Linux查询网段内所有设备
方法一：使用nmap命令
举例说明，我的计算机在192.168.199.x网段下的地址为192.168.199.234，网段子关掩码为255.255.255.0(24位子管掩码)，那么查询我的计算机在192.168.199.x下的所有设备则使用如下命令
nmap -sn 192.168.199.0/24返回数据：
Starting Nmap 7.01 ( https://nmap.org ) at 2020-03-31 11:02 CST
Nmap scan report for Hiwifi.lan (192.168.199.1)
Host is up (0.00077s latency).
Nmap scan report for chuangmi_camera_ipc009.lan (192.168.199.101)
Host is up (0.0012s latency).
Nmap scan report for HUAWEI_Mate_20.lan (192.168.199.111)
Host is up (0.087s latency).
Nmap scan report for chuangmi-plug-v3_miapDC70.lan (192.168.199.140)
Host is up (0.0030s latency).
Nmap scan report for ryan-ThinkPad-X270.lan (192.168.199.227)
Host is up (0.0012s latency).
Nmap scan report for ryan-OptiPlex-7040.lan (192.168.199.234)
Host is up (0.00026s latency).
Nmap done: 256 IP addresses (6 hosts up) scanned in 2.74 seconds
方法二：使用nbtscan命令
通过nbtscan可以直接扫描网段内全部设备，方法类似nmap（nbtscan需要sudo权限）：
sudo nbtscan 192.168.199.0/24返回信息（只返回了网段内的计算机设备，我的手机和远程摄像头都没有扫描出来，原因不明，可能因为设备网络配置的问题）：
Doing NBT name scan for addresses from 192.168.199.0/24
IP address NetBIOS Name Server User MAC address
------------------------------------------------------------------------------
192.168.199.0 Sendto failed: Permission denied
192.168.199.234 RYAN-OPTIPLEX-7 <server> RYAN-OPTIPLEX-7 00:00:00:00:00:00
192.168.199.255 Sendto failed: Permission denied
192.168.199.227 RYAN-THINKPAD-X <server> RYAN-THINKPAD-X 00:00:00:00:00:00
还可以搜索网段内指定IP地址段内的设备：
sudo nbtscan 192.168.199.100-230返回信息：
Doing NBT name scan for addresses from 192.168.199.100-230
IP address NetBIOS Name Server User MAC address
------------------------------------------------------------------------------
192.168.199.227 RYAN-THINKPAD-X <server> RYAN-THINKPAD-X 00:00:00:00:00:00以上就是Linux下查询网段内所有设备IP的方法，综合而言，根据我日常使用的经验，nmap不容易遗漏IP地址，但是查询到的信息没有nbtscan丰富直观，所以我比较推荐两种方法同时使用。