top 与 ps 还有 htop 命令都可以用来查看系统的进程信息，当然，它们也是有区别的。
简单来说，使用 ps 命令，显示的是查询时刻的瞬间状态，显示查询结果，不会刷新。而使用 top 命令，查看的信息是动态的，也就是说，top 命令进入了一个程序的交互界面，我们可以查看系统运行的实时状态，并进行自己的操作，直到手动退出。而 htop 命令用来查看单个进程的线程。
top 命令的使用
PID 进程编号 UID 有效用户编号，即展示出来的身份可能不是真实身份 USER 有效的用户名
- 进程� = Process Id nDRT = Dirty Pages Count
- USER = Effective User Name WCHAN = Sleeping in Function
- PR = 优先级 标志 = Task Flags
- NI = Nice Value CGROUPS = Control Groups
- RES = Resident Size (KiB) SUPGIDS = Supp Groups IDs
- VIRT = Virtual Image (KiB) SUPGRPS = Supp Groups Names
- SHR = Shared Memory (KiB) TGID = Thread Group Id
- 日 = Process Status OOMa = OOMEM Adjustment
- %CPU = CPU Usage OOMs = OOMEM Score current
- %MEM = Memory Usage (RES) ENVIRON = Environment vars
- TIME+ = CPU Time, hundredths vMj = Major Faults delta
- COMMAND = Command Name/Line vMn = Minor Faults delta PPID = Parent Process pid USED = Res+Swap Size (KiB) UID = Effective User Id nsIPC = IPC namespace Inode RUID = Real User Id nsMNT = MNT namespace Inode RUSER = Real User Name nsNET = NET namespace Inode SUID = Saved User Id nsPID = PID namespace Inode SUSER = Saved User Name nsUSER = USER namespace Inode GID = Group Id nsUTS = UTS namespace Inode GROUP = Group Name LXC = LXC container name PGRP = Process Group Id RSan = RES Anonymous (KiB) TTY = Controlling Tty RSfd = RES File-based (KiB) TPGID = Tty Process Grp Id RSlk = RES Locked (KiB) SID = Session Id RSsh = RES Shared (KiB) nTH = Number of Threads CGNAME = Control Group name P = Last Used Cpu (SMP) 时间 = CPU Time SWAP = Swapped Size (KiB) CODE = Code Size (KiB) DATA = Data+Stack (KiB) nMaj = Major Page Faults nMin = Minor Page Faults
