watch
Created by : Mr Dk.
2022 / 10 / 29 11:35
Hangzhou, Zhejiang, China
Background
watch 命令能够周期性地执行一条命令，并全屏打印执行结果。这非常适合监控。默认周期为两秒。
Syntax
$ watch -h
Usage:
watch [options] command
Options:
-b, --beep beep if command has a non-zero exit
-c, --color interpret ANSI color and style sequences
-d, --differences[=<permanent>]
highlight changes between updates
-e, --errexit exit if command has a non-zero exit
-g, --chgexit exit when output from command changes
-n, --interval <secs> seconds to wait between updates
-p, --precise attempt run command in precise intervals
-t, --no-title turn off header
-x, --exec pass command to exec instead of "sh -c"
-h, --help display this help and exit
-v, --version output version information and exit
For more details see watch(1).
Usage
使用 -n 参数可以调整周期运行的时间间隔，-d 参数可以高亮本次运行和上次运行之间的差异。比如监控网络时：
$ watch -n 1 -d netstat
Every 1.0s: netstat nat: Sat Oct 29 11:27:31 2022
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 nat:34510 169.254.0.55:http ESTABLISHED
tcp 0 0 nat:56196 169.254.0.138:8186 ESTABLISHED
tcp 0 1 nat:53986 10.148.188.202:http SYN_SENT
tcp 0 0 nat:ssh 112.10.216.174:38489 ESTABLISHED
tcp 0 0 nat:39234 169.254.0.55:5574 ESTABLISHED
Active UNIX domain sockets (w/o servers)
Proto RefCnt Flags Type State I-Node Path
unix 2 [ ] DGRAM 120540811 /run/user/0/systemd/notify
unix 3 [ ] DGRAM 15934 /run/systemd/notify
...
另外，使用 -c 参数可以解释输出中的颜色信息，比如 neofetch：
$ watch neofetch
Every 2.0s: neofetch zjt-lenovo: Sat Oct 29 11:24:55 2022
^[?25l^[?7l^[0m^[31m^[1m .-/+oossssoo+/-.
`:+ssssssssssssssssss+:`
-+ssssssssssssssssssyyssss+-
.ossssssssssssssssss^[37m^[0m^[1mdMMMNy^[0m^[31m^[1msssso.
/sssssssssss^[37m^[0m^[1mhdmmNNmmyNMMMMh^[0m^[31m^[1mssssss/
+sssssssss^[37m^[0m^[1mhm^[0m^[31m^[1myd^[37m^[0m^[1mMMMMMMMNddddy^[0m^[31m^[1mssssssss+
/ssssssss^[37m^[0m^[1mhNMMM^[0m^[31m^[1myh^[37m^[0m^[1mhyyyyhmNMMMNh^[0m^[31m^[1mssssssss/
.ssssssss^[37m^[0m^[1mdMMMNh^[0m^[31m^[1mssssssssss^[37m^[0m^[1mhNMMMd^[0m^[31m^[1mssssssss.
+ssss^[37m^[0m^[1mhhhyNMMNy^[0m^[31m^[1mssssssssssss^[37m^[0m^[1myNMMMy^[0m^[31m^[1msssssss+
oss^[37m^[0m^[1myNMMMNyMMh^[0m^[31m^[1mssssssssssssss^[37m^[0m^[1mhmmmh^[0m^[31m^[1mssssssso
oss^[37m^[0m^[1myNMMMNyMMh^[0m^[31m^[1msssssssssssssshmmmh^[0m^[31m^[1mssssssso
+ssss^[37m^[0m^[1mhhhyNMMNy^[0m^[31m^[1mssssssssssss^[37m^[0m^[1myNMMMy^[0m^[31m^[1msssssss+
.ssssssss^[37m^[0m^[1mdMMMNh^[0m^[31m^[1mssssssssss^[37m^[0m^[1mhNMMMd^[0m^[31m^[1mssssssss.
/ssssssss^[37m^[0m^[1mhNMMM^[0m^[31m^[1myh^[37m^[0m^[1mhyyyyhdNMMMNh^[0m^[31m^[1mssssssss/
+sssssssss^[37m^[0m^[1mdm^[0m^[31m^[1myd^[37m^[0m^[1mMMMMMMMMddddy^[0m^[31m^[1mssssssss+
/sssssssssss^[37m^[0m^[1mhdmNNNNmyNMMMMh^[0m^[31m^[1mssssss/
.ossssssssssssssssss^[37m^[0m^[1mdMMMNy^[0m^[31m^[1msssso.
-+sssssssssssssssss^[37m^[0m^[1myyy^[0m^[31m^[1mssss+-
`:+ssssssssssssssssss+:`
.-/+oossssoo+/-.^[0m
^[20A^[9999999D^[43C^[0m^[1m^[31m^[1mmrdrivingduck^[0m@^[31m^[1mzjt-lenovo^[0m
^[43C^[0m------------------------^[0m
^[43C^[0m^[31m^[1mOS^[0m^[0m:^[0m Ubuntu 22.04.1 LTS on Windows 10 x86_64^[0m
^[43C^[0m^[31m^[1mKernel^[0m^[0m:^[0m 5.10.16.3-microsoft-standard-WSL2^[0m
^[43C^[0m^[31m^[1mUptime^[0m^[0m:^[0m 1 hour, 5 mins^[0m
^[43C^[0m^[31m^[1mPackages^[0m^[0m:^[0m 780 (dpkg)^[0m
^[43C^[0m^[31m^[1mShell^[0m^[0m:^[0m zsh 5.8.1^[0m
^[43C^[0m^[31m^[1mTerminal^[0m^[0m:^[0m Windows Terminal^[0m
这都什么玩意儿啊？因为没有解析 ANSI 的颜色样式序列。加上 -c 以后：
$ watch -c neofetch
Every 2.0s: neofetch zjt-lenovo: Sat Oct 29 11:25:31 2022
25l7l .-/+oossssoo+/-.
`:+ssssssssssssssssss+:`
-+ssssssssssssssssssyyssss+-
.ossssssssssssssssssdMMMNysssso.
/ssssssssssshdmmNNmmyNMMMMhssssss/
+ssssssssshmydMMMMMMMNddddyssssssss+
/sssssssshNMMMyhhyyyyhmNMMMNhssssssss/
.ssssssssdMMMNhsssssssssshNMMMdssssssss.
+sssshhhyNMMNyssssssssssssyNMMMysssssss+
ossyNMMMNyMMhsssssssssssssshmmmhssssssso
ossyNMMMNyMMhsssssssssssssshmmmhssssssso
+sssshhhyNMMNyssssssssssssyNMMMysssssss+
.ssssssssdMMMNhsssssssssshNMMMdssssssss.
/sssssssshNMMMyhhyyyyhdNMMMNhssssssss/
+sssssssssdmydMMMMMMMMddddyssssssss+
/ssssssssssshdmNNNNmyNMMMMhssssss/
.ossssssssssssssssssdMMMNysssso.
-+sssssssssssssssssyyyssss+-
`:+ssssssssssssssssss+:`
.-/+oossssoo+/-.
mrdrivingduck@zjt-lenovo
------------------------
OS: Ubuntu 22.04.1 LTS on Windows 10 x86_64
Kernel: 5.10.16.3-microsoft-standard-WSL2
Uptime: 1 hour, 6 mins
Packages: 780 (dpkg)
Shell: zsh 5.8.1
Terminal: Windows Terminal