12.2, Linux Job management, adjustment process priority

1. Linux Job classification:

Front-end job: foreground, start with terminal, and always occupy terminal after startup

Background jobs: Background, can be launched through the terminal, but after the boot will be transferred to the background, release the terminal occupied

A job may contain multiple programs, or it can contain only one program.

2, the operation is transferred to the backstage method:

Jobs in operation: Ctrl + Z

Note: In the background, the job will be switched to a stop state

Jobs not yet running: Command &/Commands followed by a &, indicating that jobs are sent backstage

Note: Although this type of job is sent backstage, but he is still related to the terminal, if you want to send back to the background of the job to split the relationship with the terminal, the operation is as follows: #nohup Command &

3. View all jobs:

Jobs

4. Common commands for implementing job control:

#fg//Transfer the job from the background to the foreground

Usage: FG [[%]job_num]//job_num is job number,% can be omitted

#bg//Let the background stop job keep running

Usage: BG [[[%]job_num]//job_num is job number,% can be omitted

#kill//Terminate the specified job

Usage: BG%job_num//job_num is the job number,% can not be omitted, because kill's% removed means that the corresponding process is killed, not the job.

5, adjust the process priority: by adjusting the nice value, can only adjust the user's running process priority, user priority range: 100-139, the corresponding nice value is: -20,19; When the process starts, its nice value defaults to "0" and its priority is 120.

6. Nice command: Start and run the process with the specified nice value

Usage: nice [OPTION] [COMMAND [ARG] ...]

Such as:

#ps Axo Pid,comm,ni//Custom display content

#nice-N-5 htop//-n: Indicates its nice value

Note: Only the administrator can adjust the nice value down.

7. Renice Command: Manage the running process

Usage: Renice [-n] Priority [-GPU] identifier ...

such as: #renice-N-3 Htop

8. View nice values and priorities:

#ps Axo Pid,nice,priority,comm

9. Other commands:

SAR, Tsar, Iostat, Iftop, Nethog

10. Common network Client Tools: Ping, Lftp, FTP, Lftpget, wget,

ping command:

ping [-aabbddfhlnoqrruvv46] [-C Count] [-f Flowlabel] [-I interval] [-I interface] [-l preload] [-m mark] [-M Pmtudisc _option] [-nnodeinfo_option] [-W deadline] [-w timeout] [-p pattern] [-Q TOS] [-S packetsize] [-S sndbuf] [-t TTL] [-t timestamp option] [Hop ...] destination

Hping: Available during stress testing.

Traceroute command: Tracks the gateway that passes from the source host to the target host.

FTP command: FTP service command-line client tool

LFTP command: Used to replace the earlier FTP command

LFTP [-d] [-e cmd] [-P port] [-u User[,pass]] [site]

Lftp-f Script_file

Lftp-c commands

Lftp--version

Lftp--help

Lftpget command: Do not login FTP server, automatically go to download, followed by URL

Lftpget [-c] [-d] [-v] url [url ...]

-C: Breakpoint continued to pass

Example: Lftpget https://192.168.1.1/ks.cfg

wget command: Download tool, non-interactive

wget [option] ... [URL] ...

Option

-B: Perform the download operation in the background, using the generic in the script

-Q: Silent download

-o file: Where to save the download file

-C: Breakpoint continued to pass

--limit-rate=amount: Transferring files in the specified speed record

12.2, Linux Job management, adjustment process priority