Linux common commands and how to use __linux

This article detailed Linux commonly used commands and the use of methods, welcome to the collection, convenient for future use.

1. #表示权限用户 (such as: root), $ for ordinary users

Boot prompt: Login: Enter user name

Password: Enter password user is the system registered user successful landing, you can enter the corresponding user environment.

Exit Current shell, enter: Exit

2.useradd netseek Add a Netseek user

passwd Netseek to Netseek This user to set a password.

(/etc/passwd/etc/group)

Userdel Netseek Delete Account

Userdel-r Netseek Delete account with your own directory.

[For more details, see man page, and account Admin]

3. View commands

Ls-l

Show file list

Ls-al

-a displays all files and directories (LS default starts with the file name or directory name as ".") As a hidden

File, not listed)

Ls-al |grep ' ^d '

Show Table of Contents

Ls-al |grep ' ^[^d] ' queries all files in a directory that do not contain a directory

Ls-sh (man ls to view Man help.)

Linux several file types:

D indicates that this file is a directory

-Indicates that this file is a normal file

b indicates that this file is a special block device I/o file

c indicates that this file is a special character device I/O

The file command determines the type of files by probing the contents of the file

4. Create files and directories

Touch 1.txt

Cat > 2.txt (Create a file with a directional character, fill in the content, press Ctrl+d to save the content)

mkdir mywork Build mywork This directory

5. copy files or directories

CP filename1 Filename2

Cp-r dir1 DIR2 Replication Directory

CP-RF parameter f is to delete a target file that already exists without prompting

Cp-i parameters I and F, the target file will be prompted for confirmation before overwriting the target file

Is overwritten, is an interactive copy.

6. Delete files and directories (delete files or directories can be done with RM)

RM 1.c//Delete 1.c this file

RM-RF (Force delete file or directory, do not prompt when deleting.)

7. Remove the catalogue or change the file name

MV [opitons] source file or directory

[Options] Main parameters

Destination file or directory

-I: interactive operation, if the MV operation will lead to an existing target file overwrite, at this time the system asks if the heavy

Write, asking the user to answer "y" or "n",

This prevents the file from being overwritten incorrectly.

-F: Disables interaction. MV operation to overwrite an existing target file without giving any indication, specify this parameter after I

The parameters will no longer work.

MV Hello. /move the Hello directory or file to the next level.

8.alias Alias

Alias Dir= ' Ls-l ' enters Dir, which is actually equivalent to executing the LS-L

9. Control of permissions (RWX 421)

chmod +x hello.sh is assigned executable permissions.

(A detailed description of the control of permissions)

chmod Command Permission Modification usage: chmod a 8 binary number filename (rwx 421)

Eg:chmod u+x Filenmame

Just want to run for yourself, others can only read

Chown netseek.netseek mydir change user group

U: Representing the owner of the file

G: Representing the same group of users

O: Indicates other user

A: Represents all users

Opt is representative of the operation, can be:

+: Add a permission

-: Cancel a permission

=: give the given permission and revoke the original permission

and mode represents the right:

R: Readable 4

W: Can write 2

X: Executable 1

10.PWD Display current directory full path and change directory

CD Netseek into Netseek this directory

CD Exit current directory

Cd.. /go to the previous level directory.

CD-Back to previous directory

CD ~ Back to home directory

cat,more,less command.

To display the contents of a file, two different commands are: Cat print the contents of the file all the time, and more

is displayed in a separate exhibition.

Less can scroll up and down to view content.

Cat > 1.txt can fill in or copy content, press Ctrl+d to save

Cat 1.c

More 1.c

Head-n filename shows the contents of the nth line

Tail-n filename Displays the contents of the following n rows

Tail-n 20/var/log/message Displays the latest 20-line log

12. Set Linux time and date

Date command ("date MMDDHHMMYYYY.SS")

July 24, 2006 12:37, 30 seconds

Date 072412372006.30

Date-s 20:30:30 #设置系统时间为 20:30:30

Date-s 2006-7-24 #设置系统时期为 2006-7-24

Clock-r #对系统Bios中读取时间参数

Clock-w #将系统时间 (such as time set by date) to the BIOS

13. View Find Files

Several introductions:

Find path-name filename

Find/etc-name named.conf

Locate tool to search for files by file name (to first establish an index database via UpdateDB)

Localte named.conf

Whereis is looking for a binary file and will also find its Help file

Which is similar to where it is, only the set of the environment variables we set in the path of the search;

14. Killing Process

PS aux

Ps-ef |grep

Kill-9

See which process consumes the most memory

Ps-aux|sort +5n

Put programs in front of the background to perform

CP file1 File2 &

& and Ctrl+z You can use & or ctrl+z to put commands in the background to perform.

FG is the program that will be put in the background and put back in the foreground.

15.DD Command Backup

DD if= "Input_file" of= "Out_file" bs= "block_size" count= "number"

Parameters:

If: is the input file can be a device

Of: Is output file can also be a device

BS: Plan the size of a block, if not set, preset is 512bytes

Count: How many BS mean.

DD If=/etc/password Of=/tmp/passwd.bak Backup

16.mount Load a hardware device

Usage: Mount [parameters] the device mount point to load

Eg:mount/dev/cdrom

Cd/mnt/cdrom//access to the CD directory

U disk:

Mkdir/mnt/usb; (Note: Create mount directory)

Mount/mnt/sda1/mnt/usb; (Note: Mount U disk)

Now you can use the U disk, the contents of the/mnt/usb directory is the contents of the U disk;

After use, with the command to uninstall the U disk can be.

Umount/mnt/usb

Mount

List all partitions of the system

Mount-t Iso9660/dev/cdrom/mnt/cdrom

Mount-t Vfat/dev/fd0/mnt/floppy

Mount CD

Mount Floppy

Mount-t Vfat-o Iocharset=utf8,umask=000/dev/hda2/mnt/hda2

FAT32 partition

Mount

Mount-t Ntfs-o Nls=utf8,umask=000/dev/hda3/mnt/hda3

Partition

Mount NTFS

Linux-ntfs project:http://linux-ntfs.sourceforge.net/

Umount/mnt/hda3 Unloading load

Note: Before mounting the equipment, please look fdisk-l first.

17.SU switch to another identity without exiting the login

Usage: SU-L user name (switch to root if user name is default)

Eg:su-l netseek (Switch to netseek This user, will prompt for password), plus-Indicates switching to

The environment variable of the user.

Sudo leverages the permissions he can perform root execution

18.whoami,id,w,lastlog,users,groups

W View User login information

Who view current login

Last one months of user login

Lastlog check the last logon time for a particular user and format the output of the last logon log/var/log/lastlog

WhoAmI confirmed his identity.

ID prints out its UID as well as the GID. (UID: A unique identity for a user. GID: The user group identity is uniquely identified.

Each user can have only one UID and GID.

Users

Groups the user group to which the user belongs;

Finger-l Netseek Root

Finger-s or Direct finger

Allows users to query some other user's information

Eg:finger//View the user information used by the users

Finger root//view root information

19. User-used commands and execution history commands

History displays commands that the user used to kill

!! Perform the most recent command

20.uname View Linux System Information

Parameters:-A All information-R version number-N Host name

21. Establish Soft Connection

ln [-SF] source target

ln Souce-file Hard-link

LN-SF Source-file Soft-link

s indicates a soft connection, f means that if there is a file with the same name, it is overwritten.

Note: Hard links cannot be created for directories, only files can create hard links.

22. View Table of Contents

Du-sh

Directory or file

Du-m du system The default output is in kilobytes, and the parameter-M is indicated in MB.

Cat/etc/fstab

Fdisk-l

View a list of partitions

Df-h

Df-ah

23. View the resources that the Linux system occupies (top,free,uptime)

Top view background program, monitor system performance

TOP-D 2 new column every two seconds

top-d -2-p3690 View a PID

Top-b-N 2 >/tmp/top.txt The top information 2 times, and then outputs the results to/tmp/top.txt

Free-m View system memory usage

Uptime Displays the current system boot time (see how long, how many people log in, the past 1,5,15 minutes system load)

24. File Ratio software:

The CMP CMP (abbreviated by "compare") command is used to briefly indicate whether two files are different and use permissions for all users

The diff diff command is used for comparisons between two files and points to the difference between the two, and it uses permissions for all users

25. Remote operation and File transfer

SSH User@remote.machine

SCP User@remote.machine:/remote/path/local/path

Scp/local/path User@remote.machine:/remote/path

26. Compile the C + + file

Gcc

Gcc-v View GCC version

Gcc-o Test test.c 2>errfile Compile the test.c with an error message, redirect the error message to the Errfile

27.chattr +i filename Prohibit deletion, chattr-i filename cancellation prohibited

Lsattr View Hidden file properties

28. Automated implementation

At execution once

crontab Timer Cycle Execution procedure

Crontab Introduction

1 log in as root

2 # CRONTAB-E

3 Join a line

1 */12 * * */usr/sbin/ntpdate pool.ntp.org

Minutes

Small Hours

(0-59)

(0-23)

Date (1-31)

Month

(1-12)

Week

(0-6)//0 representative on Sunday

29. Shutdown and reboot:

Shutwond [-t-seconds] [-RKHNCFF] time [warning message]

-T seconds: Sets the delay time (in seconds) between warning and deletion of the two signals before switching to a different runlevel

-K issued a warning message, but not really to shutdown

-R shutdown reboot after this

-H shutdown This rear boot

-N does not go through init, by the shutdown command itself to boot work (not recommended)

When-F restarts, skips the fsck instruction and does not check the file system.

When-F restarts, force a fsck check.

-C cancels the action already being shutdown

Shutdown-h now shuts down immediately, in which time is 0,halt,poweroff or shut down, or direct init 0

Shutdown-h 20:30 system will be shut down in 8:30 tonight.

The Shutdown-h +10 system automatically shuts down after 10 minutes.

Shutdown-t3-r now reboots immediately, but in the warning and deletion processes this room,

Shutdown-k Now ' hey! Go away! Now ... ' Send a warning message, but there is no real shutdown.

Reboot

Shutdown-r now is almost the same as reboot, not related to the proposed reboot execution as follows:

Shutdown-r +30 ' The system Wiil reboot '

Shutdown-r +10 ' hey!  Go away! ' The system reboots after 10 minutes.

#sync; Sync Sync Reboot Note: Sync writes data to the hard disk synchronously

The halt command is equivalent to shutdown-h now, which means that the machine shuts down immediately.

The reboot command is equivalent to Shutown-r now, which means that it immediately resets.

30. How to change the startup mode run level

Vi/etc/inittab

Change the 5 to 3, and it will turn into character mode after startup.

StartX or init 5 can enter the graphical interface.

RunLevel Display current run level

How to switch to single user mode

Use Telinit or init (in fact Telinit is just a synbol link to init)

Telinit 1 or Init s can, of course, Telinit S is ok.

How to make Ctrl+alt+del three key failure method

#vi/etc/inittab

Add a comment before ca::ctrlaltdel:/sbin/shutdonw-t3-r now #

Then execute #telinit q, the parameter q is to Telinit again/etc/inittab

31.TAB using the TAB key, when you do not know the full name of the file or command, please press the TAB key continuously.

32.clear Clear Screen

33.DMESG |more Display boot information (view hardware information at system startup)

34. Change the performance of the program to a good level

Nice

Set Priority Nice-n-5 VI & with ROOT to a nice value of-5, used to perform VI

Renice adjustment already exists priority

35. Module-related commands

LSMOD displays modules that have been loaded into the system

Depmod analysis of the dependencies of the loading system

Modinfo display information for kernel modules

Insmod Loading Module

Modprobe Automatic Process Loading module

Rmmod Delete Module

The 36.chkconfig--list displays the status of various services and makes it easy to manage the init script with Chkconfig.

Several decompression commands for 37.linux

Compress AAA to compress AAA files into AAA. Z

compress-d aaa.z to compress aaa.z files into AAA

Gzip AAA Compression Command

gzip-d aaa.gz Decompression Command

Bzip2-z filename compression, ditto plus-D parameter decompression

Bzcat filename.bz View Compressed file contents

Tar czvf aaa.tar.gz AAA compresses catalog AAA into aaa.tar.gz

Tar-n ' 2007/03/01 '-ZCVF home.tar.gz/home in/home, is backed up by a new file in 2007/03/01.

Tar--exclude/home/cao-zxvf myfile.tar.gz/home/*/etc to back up/home,/etc, but don't/home/cao

cd/tmp; TAR-CVF-/etc | TAR-XVF-After packing the/etc/, untie/tmp directly, without producing a file.

Tar zxvf aaa.tar.gz decompression command.

Tar jxvf aaa.tar.bz2 Decompression command

Tar zxvf aaa.tar.gz-c/var/www extract aaa.tar.gz to/var/www directory

Cpio-covb > [File|device] Backup

Cpio-icduv < [file|device] Restore

38. Network command

Ifconfig display or set up a network device, you can view the current IP, similar to the ipconfig in Windows

Service Networkrestart (/etc/rc.d/init.d/network restart) Reboot network card

Ifdown eth0 off the NIC

Ifup eth0 Open Network card

Route-n View routing Table

Route add-net 192.168.20.1 netmask255.255.255.0 Dev eth0

Netstat View network connectivity

Netstat-i display of network card operation

Netstat-r View the list of routes for a host

Traceroute

Hostname Display host name

HOSTNAME-I Displays the IP of the current host name.

39. System Integration Management menu.

Setup System service Management command

NTSYSV Set up system services

40.FDISK/MBR Delete Grub

41. Database Startup

Start MySQL:

Service mysqld Start (/etc/rc.d/init.d/mysqldstart)

Mysql-uroot-p Enter the password to operate the MySQL database.

Start Oracle

Su-oracle

$lsnrctl stop

$lsnrctl start

Sqlplus/nolog

Conn/as SYSDBA (connected)

Startup

42. Install Package

RPM Package Installation:

RPM-IVH xxx.rpm

Install the RPM package

Rpm-qa--last | Less

Display packages that have been installed based on the installation date

RPM-QA |grep mysql-i Query System install MySQL package (-I, ignore case)

RPM-E to remove installed packages

RPM-E mysql*--nodpes forced deletion of related packages

RPM--test Test Installation

Rpm-qi Query MySQL Suite description information

RPM-QPL xxx.rpm View the contents of the RPM package.

RPM-QC[D] Profile and specification file

RPM-UVH Upgrade Installation

Rpmbuild--BB Specs/xxx.spec will be xxx.spec compiled into an RPM package.

Rpmbuild--rebuild packagename.src.rpm again, src.rpm compiled into an RPM package.

Source code compilation installation (classic)

./configure Check System Information (./configure--help | More help information, you can see the relevant parameter settings)

Make clean erase files left before

Make compilation

Make install Installation

Note: Source package installation, the general will first extract the file, installation process is generally above a few steps, specific description of the general opinion after the catalogue

(install,reademe description.)