Linux basic concepts and Personal notes summary (4)

Anti-counterfeiting code: Empty talk endangers, hard work hing Bang

Chapter seventh process and planned task management

One, view process information

1. View Static Process information

PS aux

2. View dynamic Process Information

Top

3. Query process information according to the conditions

Pgrep-l "Process Name"

4. View the process tree

Pstree-aup

Second, the process started

1, manual start: Front desk backstage (&)

2. Dispatch start: at (disposable), crontab (periodic)

Third, manual start, the details are shown in the notes:

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Funnel command: cat/dev/zero (table will never be read 0) >/dev/null (table will always write dissatisfied files)

Iv. conclusion of the process

1. Ctrl + C (running process)

2. Kill (PID of killing process)

Format: Kill PID Number

Option-Q table coercion

3, Killall (Kill process name)

Format: Kill all

4, Pkill (kill the process according to certain conditions)

Pkill-q-U "Zhang San" (Take user Zhang San as an example)

V. at (disposable)

Service script:/ETC/INIT.D/ATD

Format: at: Year-month-day

CTRL +D Table Submit task

Related commands:

at (set) view current time: Date

ATQ (query) modified time date-s: minutes

ATRM (delete) Date Modified: Date-s Month Day

Vi. crontab (cyclical)

Service script:/etc/init.d/crond

Format:

Time-of-day week (0, 7 for Sunday) command or Script (absolute path)

Related commands:

CRONTAB-E Edit

Crontab-l View

Crontab-r Delete

Special representations of time values:

*: Indicates any time within the range

,: Multiple discontinuous points of time that represent intervals

-: Represents a continuous range of time

/: Specify the time frequency of the interval

Prevent conflicts, as shown in the notes:

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Eighth chapter analysis and troubleshooting system failures

Considering the theoretical knowledge is difficult to understand, so will be updated in the follow-up experiment text, really hope to help everyone, thank you!

Classification of logs:

Kernel and system logs, user logs, program logs

Log Save location:

Default in:/var/log directory

Kernel and public message log:/var/log/messages

Scheduled Task log:/var/log/cron

Log message Importance:

0 Emerg (Emergency): causes the host system to become unusable

1 alert (warning): A problem that must be taken immediate action to resolve

2 Crit (severe): more serious situation

3 ERR (Error): Run error occurred

4 WARNING (Reminder): May affect the system function, need to remind the user important event

5 NOTICE (Note): Events that do not affect system functionality, but should be noted

6 info (Info): General information

7 Debug (Debug): Program or system debugging information and so on.

Prevent conflicts, as shown in the notes:

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Linux basic concepts and Personal notes summary (4)