Research on program Management and SELinux

1.jobs [-lrs]: Observe the current background in the working state, parameters,

-L: List PID numbers in addition to the job number and instruction string

-r: Enter a list of jobs running on the background run

-S: Lists only the work that is paused in the background

The + sign after the instruction executes represents the last work number that was put in the background, representing the last work number placed in the background. And more than a third job will no longer have the +/-number.

2.FG%jobnumber: Take the work in the background to the foreground to handle, parameters:

1)%jobnumber is the work number (number), this percent is optional, if not add any parameters, it will be + (last) the background work to get the foreground to execute, FG-representative will-the work number taken out to the foreground to take the run.

3.bg: Let the command working in the background run by a paused state (Ctr+z can cause the program to pause in the background), with the parameters as FG.

4.kill-signal%jobnumber;kill-l: Working in the management background, parameters,

1)-L: Lists the current signals that kill can use

2) Signal: What kind of instructions are given for the work to be followed, with Man 7 signal:

-1: Re-read the configuration file of the parameter once

-2: Represents the same action by keyboard input Ctr+c

-9: Force deletion of a job immediately

-15: Terminating a job in a normal program manner

5. Background refers to the terminal mode, can avoid ctr+c interruption of a situation, not put in the background of the system, so the background of the work management is still related to the terminal, in such a case, if it is a remote online connection of the Linux host, and will work in & mode in the background processing , the work is not completed offline, the work will not continue, it will be terminated.

6.nohup [directives and parameters]: working in the foreground of the terminal, Nohup [directives and parameters] & working in the background of the terminal. It is important to note that NOHUP does not support bash's built-in instructions, so your instructions must be external directives.

7.ps: Capture the program operation at a point in time, a few common combinations,

1) PS aux: Observe all the program data

2) Ps-ia: Observing some system data

3) PS AXJF: Together with the sub-program tree status

4) Ps-l: Check your bash program only

The parameters of each parameter:

1)-A: All of the process is shown, with the same effect as-E

2)-A: All process not related to terminal

3)-U: Effective user-related process

4) x: Usually used together with a, can list more complete information

Output format planning:

5) L: A longer, more detailed list of the PID information

6) J: Working format

7)-F: Make a more complete output

Ps-l: The meaning of the parameters:

F: the logo (flag) representing the program, which is common:

4: Indicates that the permission for this program is root

1: Indicates that this subroutine is only fork and does not actually perform exec

S: Represents the state of the program, the main state is:

R: The program is in operation

S: The program is currently in a sleep state but can be awakened

D: Sleep state that cannot be awakened, usually this program waits for IO

T: Stop state, may be in work control (background pause) or in a debug state

Z: Zombie Status, program has been terminated but cannot be removed to out-of-memory

Uid/pid/ppid: The PID number/PID number of the program that represents the program that is owned by the UID

C: Represents CPU usage in percent

The pri/ni:priority/nice abbreviation, which represents the priority that this program is being performed by the CPU, the smaller the value, the faster the program is executed by the CPU

Addr/sz/wchan: All with memory, ADDR is kernel function, which indicates which part of the program is stored, and if it is a running program, it will generally show-,/sz how much memory is used to represent this program. Wcchan Indicates whether the program is currently running

, the same as the--Indicates the operation

TTY: The terminal location of the login, using the dynamic Terminal Interface (pts/n) for remote login

Time: CPU times used, which is the CPU time that the program actually spends, not the system time

CMD: Instruction

The meaning of the parameters in the PS aux,

User: Which user account the process belongs to

PID: Process ID

%CPU:CPU Utilization

%MEM: Percentage of memory consumed

VSZ: Virtual memory used by the process (Kbytes)

RSS: Fixed memory occupied by the process (Kbytes)

TTY: This program runs the terminal equipment, tty1-6 is native, ps/0, etc., indicating that the program is connected by the network into the host

STAT: The current state of the program

Start: The time that the process was triggered to start

Time: The process actually used by the CPU

Command: The instruction actually used by the program

8. Zombie Program: Usually the cause of the zombie program is because the program should have been completed, or should be terminated for some reason, but the program's parent process can not completely say that the program ended, and the program has been in memory. Such a program after the CMD will also be connected to <defunct> indicates that the program is a zombie program

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Research on program Management and SELinux