Linux basic commands

Beginner Linux may appear to forget the command, this time should be a few common commands to write down, so that every day can knock, the days will be a long time in the mind has a deep impression. Here is my record of the common Linux commands, as well as the configuration of the service, are very practical, but for a bit of basic people:

I. Some information about Linux system logs, log configuration file syslog.conf

System logs are generally present under/var/log
The usual system logs are as follows:
Core Boot log:/VAR/LOG/DMESG
System error log:/var/log/messages
Mail system log:/var/log/maillog
FTP System log:/var/log/xferlog
Security information and System login and network connection information:/bar/log/secure
Login record:/var/log/wtmp
News log:/var/log/spooler
RPM Package:/var/log/rpmpkgs
XFree86 log:/var/log/xfree86.0.log
Boot log:/var/log/boot.log
Cron (custom task Log) log:/var/log/cron
Network:/etc/sysconfig/network-scrip/ifcif-etho

Ii. Common Commands

Find./-mtime 0: Returns files that have been modified in the last 24 hours./Represents the folder you need to find


/ETC/MOTD displaying a message when Telnet


Sed-n ' 5,10p ' filename so you can view only the lines 5th through 10th of the file.


Yum instll xxx Install XXX pack

/etc/inittab System kernel Commands


MKFS-T ext3-c/DEV/SDB3 formatted partition

Fdisk-l Disk Details

FDISK/DEV/SDB1 | Fdisk-l Disk Partitioning


chkconfig [Service]--list status|stop service turned off


/etc/fstab Expansion Slot Boot mount


/etc/sysconfig/iptables//Firewall configuration file
Service Iptables Stop/start//Startup and shutdown
-A input-s 192.168.0.3-p tcp--dport 22-j ACCEPT firewall configuration: Only allow this machine to connect with SSH
Iptables-i input-s 59.151.119.180-j DROP//IP connection,
Iptables-i input-s 211.1.0.0/16-j DROP//IP segment


Ulimit-f 10240 Limit the capacity of users to create files

Parted/dev/sdb Print View divider slot

cp/etc/skel/. {BASH_PROFILE,BASHRC}

Ifconfig | grep ' inet addr ' | awk ' {print $} ' | Sed ' s/addr://g ' View a column field

Read-p Man-Machine interaction, enter a value to execute

NETSTAT-T-u L-P Network tracking

DMESG | Grep-i HD ETH Analytics core message

Vmstat-a-fs-s-d-p System resource change, detection


Vim ~/.BASHRC BASHRC can set shortcut commands

Alias so= ' source ~/.BASHRC '   Save settings


alias ps11= ' echo ps1= ' [\[email protected]\h \w \a #\#]\$ "'   terminal display


alias sk= ' Echo cp/etc/skel/.{ BASG_PROFILE,BASHRC} ~   Works when terminal displays an error


alias grep= ' grep--color=auto '   grep display color


Alias Al= ' vim ~/.BASHRC '    alias shortcut variable


export   |   set       View Variables


setup  Supplemental Note: Setup is a setup utility that provides a graphical interface for how to do this



Cal 2017 8 to view calendar

Usermod-g stdent (group) index (user)    change user-owned group

Chgrp stdent (group) ipconfig (file)      Change file owning group

Chown Liu (user) ipconfig (file)      change file user

useradd   create user
groupadd  Creating a group


Path= "$PATH":/root shortcut PATH usage


rpm-ivh  xx.rpm    Install RMP package



DD if=/dev/hdc1 of=/tmp/boot.whole.disk   backup

restore-t-f/root/boot.dump     Restore files or directories

Three, detailed settings

Firewall configuration

IPTABLES-F//Clear Configuration

/etc/rc.d/init.d/iptables

1) effective after reboot
Open: Chkconfig iptables on
OFF: Chkconfig iptables off

2) immediate effect, failure after reboot
Open: Service iptables start
Close: Service iptables stop

It should be stated that for other services under Linux, the above command can be used to perform the open and close operations.

When the firewall is turned on, make the following settings, open the relevant port,
Modify the/etc/sysconfig/iptables file to add the following:
-A rh-firewall-1-input-m state--state new-m tcp-p TCP--dport 80-j ACCEPT
-A rh-firewall-1-input-m state--state new-m tcp-p TCP--dport 22-j ACCEPT

Network settings:

/etc/sysconfig/network-scripts/ifcfg-eth0 Network Configuration

Onboot=yes//boot up
Bootrpoto=static//Static IP
dns1=192.168.1.1//dns
ipaddr=172.16.2.1
netmask=255.255.255.0//Subnet mask
gateway=172.16.1.1//Gateway
Service Network Restart Restart Network

To restrict IP logons:

/etc/hosts.deny Deny Login list

/etc/hosts.allow Allow Login List

Generally use the Deny login list to set all IP
Like what
Sshd:all

Then set the IP you want to allow in the Allow login list
Like what
sshd:10.10.10.1
Sshd:192.168.1.1:allow

Crontab Scheduled Tasks

Crontab-l//List
CRONTAB-E//Edit
crontab-d//delete

Service Crond.service

Basic format:
* * * * * command
Time-sharing Weekly command

The 1th column represents minutes 1~59 per minute with * or */1
The 2nd column represents the hour 1~23 (0 means 0 points)
The 3rd column represents the date 1~31
The 4th column represents the month 1~12
5th Column Identification Number Week 0~6 (0 = Sunday)
6th List of commands to run

Shell L Script Debugging method

-N
Read the command in the script but not execute it to check for syntax errors in the script

-V
Executes scripts while printing executed script commands to standard error output

-X
Provides trace execution information and prints each command and result that executes sequentially

Touch command (useful when writing scripts)

CC means century
YY represents the year
MM Indicates the month
DD represents the day
HH denotes hours
mm = minutes
SS = Seconds
201001311200.34
CCYYMMDDHHMM SS

Touch xxxx//create XXX Text

-T: can be followed by time, in the format described above
-D: Follow-up time
-A: Only modify access time//state changes, such as executed, or read
-C: Modify only the CTime time without creating the file//permissions and attributes being changed
-M: Modify only Mtime//content changes

Change issue file date to 2008/07/15 13:13
Touch-t 0807151313/etc/issue
Touch-m-D 0807151313/etc/issue
touch-acmr/bin/ls/etc/sh.conf time to change the last time to a previous file

Usage of Yum
Yum Install all installed
Yum Install Package1 installs the specified installation package Package1
Yum groupinsall group1 Installer group group1

Yum Remove & #124; Erase Package1 Remove Package Package1
Yum groupremove group1 Remove a program group group1
Yum deplist package1 Viewing program package1 dependencies


Yum Install Setuptool installs setup, but only authentication configuration is available after installation using Run Setup.

If you want to configure IP, install System-config-network-tui.

Yum Install System-config-firewall-tui installs the graphical firewall configuration tool.

Yum list system-config* all installed.

Display of dates

Date ' date +%y%m%d-%k ' = 20160531//' This is the key above the TAB key, not the single quotation mark

%a: Day of the Week (Sun. Sat)
%A: Day of the Week (Sunday). Saturday)
%b: Month (Jan). DEC)
%B: Month (January). December)
%c: Displays the date and time directly
%d: Day (01..31)
%d: Show date directly (MM/DD/YY)
%h: With%b
%j: The first day of the Year (001..366)
%m: Month (01..12)
%u: Week of the Year (00..53) (in Sunday as the first day of the week)
%w: The day of the Week (0..6)
%W: Week of the Year (00..53) (with Monday as the first day of the week)
%x: Show date directly (MM/DD/YY)
%y: Last two digits of the year (00.99)
%Y: Full year (0000..9999)
%: Print out
%%n: Next line
%t: Jump Grid
%H: Hours (00..23)
%I: Hours (01..12)
%k: Hours (0..23)
%l: Hours (1..12)
%M: minutes (00..59)
%p: Show local AM or PM
%r: Direct Display time (12-hour format, HH:MM:SS [ap]m)
%s: The number of seconds from January 1, 1970 00:00:00 UTC to date%s: seconds (00..61)
%T: Direct Display time (24-hour system)
%x: Equivalent to%h:%m:%s
%Z: Show Time zone

File comparison operations (useful when writing scripts)

-e filename true if filename exists [-e/var/log/syslog]

-D filename True if filename is a directory [-d/tmp/mydir]

-F filename True if filename is a regular file [-f/usr/bin/grep]

-L filename True if filename is a symbolic link [-l/usr/bin/grep]

-R filename True if filename is readable [-r/var/log/syslog]

-W filename if filename is writable, true [-w/var/mytmp.txt]

-X filename is true if filename is executable [-l/usr/bin/grep]

Filename1-nt filename2 If filename1 is newer than filename2, then true [/tmp/install/etc/services-nt/etc/services]

Filename1-ot filename2 If filename1 is older than filename2, then true [/boot/bzimage-ot Arch/i386/boot/bzimage]

String comparison operators (note the use of quotation marks, which is a good way to prevent whitespace from disturbing the code)

-Z String True if string length is zero [-Z $myvar]

-N String if string length is nonzero, true [-N $myvar]

string1 = string2 true if string1 is the same as string2 [$myvar = one of the three]

String1! = string2 true if string1 is different from string2 [$myvar! = one, three]

Arithmetic comparison operators

Num1-eq num2 equals [3-eq $mynum]

Num1-ne num2 Not equal to [3-ne $mynum]

Num1-lt num2 less than [3-lt $mynum]

Num1-le num2 less than or equal to [3-le $mynum]

NUM1-GT num2 greater than [3-GT $mynum]

Num1-ge num2 greater than or equal to [3-ge $mynum]

Iv. Text Manipulation commands

SED usage:

Sed ' 1d ' ab delete line 1th
Sed ' $d ' ab delete last line
Sed ' 1,2d ' ab #删除第一行到第二行

Sed-n ' 1p ' ab #显示第一行
Sed-n ' $d ' ab #显示最后一行

Sed ' 1,3a drink tea ' ab #第一行到第三行后增加字符串 "Drink Tea"

SED ' 1c Hi ' AB #第一行代替为Hi

Sed-n '/ruby/p ' ab | Sed ' s/ruby/bird/g ' #替换ruby为bird
Sed-n '/ruby/p ' ab | Sed ' s/ruby//g ' #删除ruby

Sed-i ' $a bye ' ab #在文件ab中最后一行直接输入 "Bye"





awk usage:

Awk: Performs an operation on a single line of the file in solitude.

Awk-f ":" ' {print $1,$4} ': Use ': ' to split the line and print the first fourth field in this row

<, <=, = =,! =, >=, ~ match regular expressions,!~ mismatched regular expressions

Match: awk ' {if ($4~/asima/) print $} ' temp indicates that if the fourth field contains Asima, the entire bar will be printed

Exact match: awk ' $3== ' {print $} ' temp only prints records with Field 3 equal to ' 48 '

Mismatch: awk ' $!~/asima/' temp prints entire records that do not contain Asima

Not equal to: awk ' $! = ' Asima ' temp

Less than: awk ' {if ($1<$2) print $ "is smaller"} ' temp

Set case: awk '/[gg]reen/' temp prints a whole strip of records containing green, or green

Any character: awk ' ~/^...a/' temp prints the fourth character in the 1th field is a record, the symbol ' ^ ' represents the beginning of the line, conforms to '. ' Represents any character

or relationship matching: awk ' $0~/(ABC) | (EFG)/' temp ' when using |, the statement needs to be enclosed

and relationship: awk ' {if ($1== "a" && $2== "B") print $} ' Temp

Or or relationship: awk ' {if ($1== "a" | | $1== "B") print $} ' Temp







Cut usage:

-B: Split in bytes. These byte locations will ignore multibyte character boundaries unless the-n flag is also specified.
-C: Split in characters.
-D: Custom delimiter, default is tab.
-F: Used with-D to specify which area to display.
-N: Cancels splitting multibyte characters. Used only with the-B flag. If the last byte of the character falls within the range of <br/> indicated by the List parameter of the-B flag, the character will be written out;

Who|cut-b 3 #每行第三个字节
Who|cut-b 3-5,8 #第三到五, and eighth byte

Cat Tab_space.txt |cut-d '-F 1 #区域以空格为分割, take the first paragraph






Sort usage:

To sort by a unit of action, by comparison, by the beginning of a letter.

-U Remove Duplicate rows

-R Descending

Sort-r number.txt-o number.txt #重定向文件要-O

V. Decompression/Compression commands

TAR-ZXF apr-1.4.5.tar.gz

. tar
Unpacking: Tar xvf Filename.tar
Package: Tar cvf filename.tar DirName
(Note: Tar is packaged, not compressed!) ）
———————————————
. gz
Decompression 1:gunzip filename.gz
Decompression 2:gzip-d filename.gz
Compression: gzip FileName
. tar.gz and. tgz
Decompression: Tar zxvf FileName.tar.gz
Compression: Tar zcvf FileName.tar.gz DirName
———————————————
. bz2
Decompression 1:bzip2-d filename.bz2
Decompression 2:BUNZIP2 filename.bz2
Compression: Bzip2-z FileName
. tar.bz2
Decompression: Tar jxvf FileName.tar.bz2
Compression: Tar jcvf FileName.tar.bz2 DirName
———————————————
. BZ
Decompression 1:bzip2-d filename.bz
Decompression 2:BUNZIP2 filename.bz
Compression: Unknown
. tar.bz
Decompression: Tar jxvf FileName.tar.bz
Compression: Unknown
———————————————
. Z
Decompression: uncompress filename.z
Compression: Compress FileName
. Tar. Z
Decompression: Tar zxvf filename.tar.z
Compression: Tar zcvf filename.tar.z DirName
———————————————
. zip
Decompression: Unzip Filename.zip
Compression: Zip Filename.zip DirName

Linux basic commands