查看top帮助信息
不管linux还是unix，大多数命令都是支持man命令来查看帮助信息的。
语法是下面这样，进入到交互界面后，用法类似vi，然后按「q」可以退出，输入「？」再输入关键字，可以查询相关关键字：
man top
帮助信息回显：
TOP(1) User Commands TOP(1)
NAME
top - display Linux processes
SYNOPSIS
top -hv|-bcHiOSs -d secs -n max -u|U user -p pid -o fld -w [cols]
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-p :Monitor-PIDs mode as: -pN1 -pN2 ... or -pN1,N2,N3 ...
Monitor only processes with specified process IDs. This option can be given up to 20 times, or you can provide a comma delimited list with up to 20 pids. Co-mingling both approaches is permitted.
A pid value of zero will be treated as the process id of the top program itself once it is running.
This is a command-line option only and should you wish to return to normal operation, it is not necessary to quit and restart top -- just issue any of these interactive commands: '=', 'u' or 'U'.
The 'p', 'u' and 'U' command-line options are mutually exclusive.
执行命令
找到帮忙信息之后，在「top」后面接上参数 「-p」就可以，还可以接多个这样的参数。下面是实例。
top -p222 -p235
结果预览
top - 10:59:27 up 8 days, 23:04, 33 users, load average: 19.29, 18.88, 15.68
Tasks: 2 total, 0 running, 2 sleeping, 0 stopped, 0 zombie
%Cpu(s): 28.0 us, 2.2 sy, 0.0 ni, 66.1 id, 3.5 wa, 0.0 hi, 0.1 si, 0.0 st
KiB Mem: 13192180+total, 12092056+used, 11001252 free, 58405476 buffers
KiB Swap: 13410816+total, 75264 used, 13403289+free. 34504364 cached Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
222 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kworker/42:0H
235 root 20 0 0 0 0 S 0.0 0.0 0:01.74 ksoftirqd/45
小结
遇到不会的Linux命令，不要慌、莫着急，用「man」查看帮助信息，帮忙信息太多，可以用用「/」或者「？」加上关键字可以搜索，可以说非常方便。还有一点就是多实践操作。
