A. Check process
1. Understanding the relationship between programs and processes
2. Review process information PS
View the current time is a static process
ps command Linux operating system is the most commonly used process viewer tool, mainly used to display the currently running include
static snapshot of the complete information of each process. By different command options, you can selectively view process information.
a: displays all process information in the current terminal, including processes of other users. And "x" option will combine
all the process information display system.
u: Use user-based format of the output process information.
x: Displays the current user process in all the terminal.
** 1. Understand the meaning of information process
USER: name of the user account to start the process.
PID: The process digital ID number in the system, is unique in the current system.
% CPU: The percentage of CPU usage.
% MEM: The percentage of memory usage.
VSZ: occupancy size of the virtual memory (swap space).
RSS: occupy resident memory size (physical memory).
TTY: indicates that the processes are running on which terminal. "?" Represents the unknown or no terminal.
STAT: Displays the current status of the process, such as S (sleep), R (run), Z (dead) <(high priority),
N (lower priority), s (the parent process), + (foreground process) . Of the process is in a state of dead hand should be
moving terminated.
START: start time of the process.
TIME: The process of CPU time.
COMMAND: name of the command to start the process.
2.ps -elf
-e: display information about all processes within the system.
-l: use long (Long) format to display process information.
-f: use the full (Full) format to display process information.
PPID: the current process of the parent process
PRI: user mode priority
NI: kernel mode priority (-29 to 19, the lower the value, the higher the priority)
ADDR: - Running
SZ: take up memory swap partition
WCHAN: current process kernel name
3.top command to view a dynamic process ranking information, refreshed every three seconds
sy: occupied by the kernel
ni: priority scheduling occupied
id: idle the CPU
WA: the I / O read and write occupied
hi: Hard thread holds
si: soft thread holds
st: virtual occupancy
buff / cache: Cache
avail Mem: physical footprint
C bond check the CPU usage
M key to view memory usage
Q key to exit Review
According to conditions of see process information pgrep
1.pgrep -l -u specifies the user to view and PID
2. List processes information in a tree structure
Specifies the user pstree - ap zhangsan
Start-up mode II. Process **
In the background
1. Taiwan before and after the scheduling process
2. terminate processes running
Directly to the user kicked zhangsan
III. Scheduled Tasks
1. Disposable Scheduled Tasks
2. Periodically scheduled task
