Liunx basic commands (shell basic priority adjustment)

Hello everyone, this time we will introduce some network configurations under liunx, simple basic optimization of shell, and level adjustment first. There are also some commands for you to take a look.

Statement: I like to share with others. I am happy, that is, to make everyone happy. Some of my posts are my previous study notes, and some of my questions can be easily recorded, I also wrote it when I suddenly remembered it. No matter how it is, it is my own experience and experience. I hope everyone can learn and make progress together.

Pid indicates that you are a sub-process)

Ppid is the parent process)

Process top \ u95f4 \ u547d \ u4ee4

\ U6309m \ u662f \ u5185 \ u5b58 \ u6392 \ u5e8f

\ U6309c \ u662fcpu \ u6392 \ u5e8f

Pid user pr ni virt pes shr s % CPU % mem time + COMMAND

PID value: User priority virtual memory size actual memory size shared memory size status percentage of CPU percentage of memory cumulative CPU

Switch back-end

The concurrency status means that the frontend and backend work together and the backend work faster than the front-end, but the CPU is wasted.

[Root @ localhost ~] # Xclock table

[Root @ localhost ~] # Xclock-update 1 plus a second stitch

[Root @ localhost ~] # Xclock-update 1 & run in the background

Converting a running foreground program to a background program

Ctrl + z stop and drop into the background

View the background:

Jobs

The background program continues to run in the background:

Bg 1 No)

Foreground program running:

Fg 1 No)

[Root @ localhost ~] # Jobs

[1] Running xclock-update 1 & background execution)

[2]-previously run) Running xclock-update 1 Running on the foreground)

[3] + currently Running) Running xclock-update 1 &

View the xclock PID

[Root @ localhost ~] # Ps aux | grep xclck

If you open a file on a terminal

Press ctrl + z to pause and exit

Press fg to continue execution on the foreground

Kill a process or program:

Kill % 1 pid) killed normally

Kill-9 1pid) to force a process or program to be killed

Kill all httpd services.

Killall httpd

Xkill is fun !!

Ctrl + ait + return key restart graphical interface

View process ID:

Kill-l

Kill-1 suspended)

Kill-9 he killed it forcibly)

Kill-15 Stop Suicide)

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Priority adjustment:

Maximum priority-20) Minimum priority 19)

Nice-nnks value)-20 priority) httpd program or service) when this program is not executed, it is equivalent to using

Adjust the pid twice)

Renice 10 priority level)-p (pid) 6020 previous pid) ongoing programs use pid to Change Priority Level

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Advanced commands:

View 20 rows of the passwd file

Cat/etc

View the output of hello world

Echo "hello world" | rev

View the upstream/downstream output of hello world

Echo "hello world" | tac

Display the number of words in a file

Wc-l rows-w words-c characters

Sort

Sort aa.txt by the first number

Sort-n aa.txt is sorted by the entire number

Sort-u aa.txt sort to remove duplicate rows

Sort-r aa.txt reverse sorting

Uniq aa.txt remove consecutive duplicate rows

Uniq-u aa.txt displays non-duplicate rows

Show duplicate rows for uniq-d aa.txt

Uniq-d-c

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Grep Filtering: The entire row is filtered out by the keyword.

[Root @ localhost ~] # Grep root/etc/passwd filter root user information

Root: x: 0: 0: root:/bin/bash

Operator: x: 11: 0: operator:/root:/sbin/nologin

Grep-v halt $/etc/passwd is not reversed with the end of halt

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Cut

Cut-d:-f field) 1/etc/paasswd truncate the first root Information

Cut-d:-f field) 1, 6/etc/paasswd intercepts the information of segments 1 and 6

Cut-d:-f field) 1-6/etc/paasswd intercepts information from 1 to 6

Cut-c characters) 1, 3/etc/paasswd

The header-3 file starts with three lines

Three lines at the end of the tail-3 File

Stat aa.txt displays details

Exercise:

1. Calculate the number of users in your system that can log on to the system [root @ localhost ~] # Grep-v nologin $/etc/passwd | wc-l

6

Cat/etc/passwd | grep-c bash

Cat/etc/passwd | grep/bin/bash | wc-l

Cat/etc/passwd | grep/bin/bash | cut-d:-f7 | uniq-c

Cat-n/etc/passwd | grep/bin/bash | cut-d:-f1, 7 | cat-n

2. ifconfig eth0 | awk-F': | + ''/Bcast/{print $4 }'

192.168.1.1

3. stat aa.txt

File: “aa.txt"

Size: 34 Blocks: 8 IO Block: 4096 General Files

Device: 802 h/2050d Inode: 48922685 Links: 1

Access: (0644/-rw-r --) Uid: (0/root) Gid: (0/root)

Access: 12:06:11. 000000000 + 0800

Modify: 12:06:11. 000000000 + 0800

Change: 12:06:11. 000000000 + 0800

[Root @ localhost ~] # Ifconfig eth0 | head-2 | tail-1 | cut-d:-f 2 | cut-d ''-f1

192.168.1.77

Show only time

[Root @ localhost ~] # Stat aa.txt | cut-d ''-f 3 | cut-d.-f 1 | tail-3

13:12:47

13:12:47

13:12:47

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Shell Basics

!! Before executing a previous command

Commands used by history

Ls! $ Previous Parameter

! The last if command after if is not easily referenced)

Redirection character

> The standard output is correct. If the file exists, the output is overwritten. If the file does not exist, the output is created.

> The standard output is correct. If the file exists, it is appended. If the file does not exist, it is created.

2> standard error output. If the file exists, it will overwrite it. If the file does not exist, it will be created.

2> standard error output. If the file exists, it is appended. If the file does not exist, it is created.

0 standard input

&> Both correct and error messages are required.

/Proc pseudo file 222pid) fd directory

0 indicates that the standard is entered correctly.

1 indicates that the standard output is correct.

2 indicates error output

[Root @ localhost tmp] # touch aa. sh use. sh as a script

Automatic User Creation

Write scripts

#! /Bin/bash: what is the meaning of the command?

# Add User scripts

For I in {1 .. 50} I loops in 1 to 50

Do starts execution)

Ehco "create new user please wait"

Sleep 2 sleep) 2 seconds

Usera

User $ I

Echo "set your passwd now !!"

Echo 123 | passwd -- stdin user $ I &>/dev/null (black hole folder eats characters)

Echo "created successfully"

Done end)

Judgment script:

#! /Bin/bash

# Determining whether a file exists

If (if) [-f/tmp/aa.txt]

Then (if any)

Echo "file to exist"

Sleep 1

Ls-l/tmp/aa.txt

If else does not exist)

Echo "creating"

Sleep 1

Touch/tmp/aa.txt

Fi

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Cyclic script

#! /Bin/bash

# Add User scripts

For I in {1 .. 10}

Do

Echo "create user $ I now !!!!! Please wait !!!! "

Sleep 1

Useradd user $ I

Echo "Set user $ I password now !!!!! "

Echo 123 | passwd -- stdin user $ I &>/dev/null

Echo "The create user $ I success !!!!! "

Done

Script judgment

#! /Bin/bash

# Determining whether a file exists

If [-f/tmp/aa.txt]

Then

Echo "the file is cunzai !!!!! Display now !!! 1"

Sleep 1

Ls-l/tmp/aa.txt

Else

Echo "the file is now cunzai !!! Create it now !!!! "

Sleep 1

Touch/tmp/aa.txt

Fi

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Network;

View Nic status in mii-tool

Ifconfig

Restart Nic

[Root @ localhost network-scripts] # service network restart

Lo, this Nic is a local back-to-back Nic. This Nic cannot be moved. Its address will always be 127.0.0.1.

Eth0 Link encap: Ethernet HWaddr 54: E6: FC: 71: 17: 45 (mk address)

Inet addr: 192.168.1.77ip v4) Bcast: 192.168.1.255 broadcast address) Mask: 255.255.255.0 subnet Mask)

Inet6 addr: fe80: 56e6: fcff: fe71: 1745/64 Scope: Link

Up broadcast running multicast mtu: 1500 maximum transmission unit) Metric: 1

RX packets: 84492 number of packets received) errors: 0 dropped: 0 overruns: 0 frame: 0

TX packets: 4460) errors: 0 dropped: 0 overruns: 0 carrier: 0

Collisions: 0 FIG: 1000

RX bytes: 11757894 (11.2 MiB) TX bytes: 310768 (303.4 KiB)

Interrupt: 225 Base address: 0x8000

Temporary modification:

Ifconfig eth0 192.168.1.77

Permanently modify the NIC configuration file

Vim/etc/sysconfig/network-scripts/ifcfg-eth0

Nic alias: Virtual Nic

Ifconfig eth0: 0 192.168.1.66

Permanent change:

Copy A ifcfg-eth0: 0

Change the name to eth0: 0.

Restart the service

Enable and disable NICs

Ifconfig eth0 up

Ifconfig eth0 down

Ifup eth0 enable Nic

Ifdown eth0 disable Nic

; A command at the front is executed no matter whether the execution is successful or not.

& The front-end command is successfully executed, and the back-end command is executed

Resolve the mik address through ping

Arping 192.168.1.33

Arp checks the connection with itself

Route DNS host name

View the route table without parsing the Host Name

Traceroute www.sina.com uses multiple routes to sina

Enable the graphic Network Configuration:

Setup

Root @ localhost ~] # LANG = en_us English

[Root @ localhost ~] # LANG = zh_CH.UTF-8 Chinese

In text mode or in English

First, configure the network.

The second is automatic DHCP retrieval.

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