[linux命令] 之watch

watch -n 2 -d date

-n : 间隔时间（秒），默认2s

-d：高亮变更部分

-t：不显示标题 

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).