Shulou(Shulou.com)06/02 Report--

One, one. The relationship between programs and processes

The program belongs to static code; it is saved on a hard disk, mobile device or CD; you can use it if you need to install it.

The running of the process needs to be judged by cpu, and then the process is saved in memory; the process is dynamically executed and the program runs constantly; a parent process contains multiple child processes.

two。 Common options for viewing static process information in PS

A displays all processes of the current terminal

U process information of the current user

X displays the progress of the current user in all terminals

-e View processes in memory

-l display process information in long format

-f complete process information

1) View the progress of all terminals of the user

User: account

PID: the ID number of the process

% cpu:cpu occupancy information

% MEM: memory footprint information

VSZ: virtual memory

RSS: physical memory usage

TTY: the terminal on which the process is running

STAT: process status, S hibernation, R running, Z deadlock, > high priority process, N low priority, S parent process, + foreground running

START: time to start the process

TIME: take up CPU time

COMMAND: name of the startup process

2) View the processes running in memory

3) View the dynamic processes on the computer and update them every 3 seconds

4) pgrep filter process information

-l displays the process name or ID

-u user

-t terminal

5) display the details of the process tree

3. Process startup management

1) the way the process runs

Front desk: now the user interface, you must run other tasks after the task is finished.

Background: the program runs in the background and does not affect other user operations

2) how the process is put in the background

Ctrl+z

3) View background process information and display process details (the first process in the background is transferred to the foreground to run)

4. Kill process

1) the way to kill the process

Kill

Killall

Pkill

2) use kill to kill processes and forcibly kill processes

II. Planning tasks

1. Roles and types of scheduled tasks

1) the role of scheduled tasks

Periodic repetitive operations are implemented using scheduled tasks

2) types of scheduled tasks

Schedule tasks at once

Periodically schedule tasks

two。 Configure one-time scheduled tasks

3. Periodically plan tasks

1) options for the crontar command

-e Editing scheduled tasks

-u specify the user who runs the scheduled task

-l View the list of scheduled tasks

-r Delete scheduled tasks

2) scheduled task control bit field

3) the common symbolic functions of fields

4) create periodic scheduled tasks

5) View cycle scheduled tasks

6) Delete scheduled tasks

7) start the scheduled task service

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