display who is logged in and what they are doing
The w utility prints a summary of the current activity on the system, including what each user is doing. The first line displays the current time of day, how long the system has been running, the number of users logged into the system, and the load averages. The load average numbers give the number of jobs in the run queue averaged over 1, 5 and 15 minutes.
The fields output are the user’s login name, the name of the terminal the user is on, the host from which the user is logged in, the time the user logged on, the time since the user last typed anything, and the name and arguments of the current process.
It is similar to top, but allows you to scroll vertically and horizontally, so you can see all the processes running on the system, along with their full command lines
其实工具都只是表层, 最底层的还是读取/proc下的文件, 具体在每个工具的man手册都有介绍。
还有一个比较强大的工具dstat, 集合了vmstat, iostat, ifstat等工具的功能, 并且输出是颜色高亮
比如上面执行过命令是ping wutianqi.com, 想再执行, 可以