Linux Common operating instructions (for interview purpose)

Linux: Free open source, multi-user multitasking, derived from a number of ancillary versions, such as the common Redhat ...

Common directives

LS Display file or directory

-l list File details L (list)

-a lists all files and directories under the current directory, including Hidden A (all)

mkdir Creating a Directory

-P Create directory, if no parent directory, create p (parent)

CD Switch Directory

Touch creates an empty file

Echo creates a file with content.

Cat View File Contents

CP Copy

MV Move or rename

RM Delete File

-R Recursive Delete, can delete subdirectories and files

-F Force Delete

Find searches a file system for a file

WC statistics Text line number, word count, number of characters

Grep finds a string in a text file

RmDir Delete Empty Directory

Tree structure display directory, need to install tree package

PWD Displays the current directory

LN creates a linked file

More, less pagination displays text file contents

Head, tail display file header, tail content

CTRL+ALT+F1 command line full-screen mode

System administration Commands

Stat Displays details of the specified file, more detailed than LS

Who shows online login

WHOAMI Show current Operation user

Hostname Display host name

Uname Display System Information

Top dynamic display currently consumes the most resources process information

PS Display transient process status Ps-aux

Du view directory size Du-h/home with units display directory information

DF View disk size df-h with unit display disk information

Ifconfig Viewing network conditions

Ping Test network connectivity

Netstat Displaying network status information

Man command won't work, find men like: Guy ls

Clear Clear Screen

Alias renamed the Command as: Alias showmeit= "Ps-aux", in addition to de-use Unaliax Showmeit

Kill kills the process, you can first view the process ID with the PS or Top command, and then kill the process with the kill command.

Packaging compression-related commands

Gzip:

BZIP2:

Tar: Packaging compression

-C Archive File

-X Compressed file

-Z gzip Compressed file

-j bzip2 Compressed Files

-V shows the compression or decompression process V (view)

-F Use file name

Cases:

TAR-CVF/HOME/ABC.TAR/HOME/ABC only packaged, not compressed

TAR-ZCVF/HOME/ABC.TAR.GZ/HOME/ABC packaged and compressed with gzip

TAR-JCVF/HOME/ABC.TAR.BZ2/HOME/ABC packaged and compressed with bzip2

Of course, if you want to decompress, just replace the above command TAR-CVF/TAR-ZCVF/TAR-JCVF "C" in the "X".

Shut down/Restart the machine

Shutdown

-R shutdown Restart

-H shutdown does not restart

Now turn the machine off.

Halt shut down the machine

Reboot restart

Linux Pipelines

Use the standard output of one command as the standard input for another command. That is, the combination of several commands to use, the latter command in addition to the results of a previous command.

Example: Grep-r "Close"/home/* | More in the home directory to find all files, including close files, and paging output.

Linux Package Management

dpkg (Debian package) management tool with a. deb suffix. This approach is suitable for systems that are not networked.

For example, install the tree command installation package, first upload tree.deb to the Linux system. Then install it using the command below.

sudo dpkg-i tree_1.5.3-1_i386.deb installation software

sudo dpkg-r tree Uninstall software

Note: There are several ways to upload tree.deb to a Linux system. Vmwaretool, use of Mount mode, use of WINSCP tools, etc.;

APTAdvanced Packaging tool. This method is suitable for the system to be able to connect the internet situation.

Still take tree as an example

sudo apt-get install tree

sudo apt-get remove tree unload tree

sudo apt-get update software

sudo apt-get upgrade

Convert the.rpm file to. Deb file

. RPM is the software format used by Redhat. cannot be used directly under Ubuntu, so you need to convert it.

sudo alien abc.rpm

Vim use

Vim three modes: Command mode, insert mode, edit mode. Use ESC or I or: to toggle the mode.

Command mode:

: Q exit

: q! Force exit

: Wq Save and exit

: Set number Displays line numbers

: Set Nonumber hidden line number

/apache find Apache in the document press N to jump to the next, Shift+n previous

YYP Copy the cursor line, and paste

H (move left one character ←), J (next line ↓), K (previous line ↑), L (move right one character →)

User and User group management

/etc/passwd Storing user accounts

/etc/group Storage Group Account

/etc/shadow Store password for user account

/etc/gshadow Password to store user group account

Useradd User Name

Userdel User Name

AddUser User Name

Groupadd Group Name

Groupdel Group Name

passwd root sets the password for root

Su Root

Su-root

/etc/profile System Environment variables

Bash_profile User Environment variables

. BASHRC User Environment variables

SU user switches the user and loads the configuration file. bashrc

Su-user switch User, load configuration file/etc/profile, load Bash_profile

User and user groups for changing files

sudo chown [-r] Owner[:group] {file| Directory}

For example: Also take jdk-7u21-linux-i586.tar.gz as an example. belongs to user Hadoop, group Hadoop

You want to switch the users and groups to which this file belongs. You can use commands.

sudo chown root:root jdk-7u21-linux-i586.tar.gz

File Rights Management

Three basic permissions

R read value represented as 4

The W write value is represented as 2

X executable value represented as 1

, the permissions for the jdk-7u21-linux-i586.tar.gz file are-rw-rw-r--

-rw-rw-r--altogether 10 characters, divided into four segments.

The first character "-" indicates a normal file, and the "L" link may also appear in this location; "D" means the directory

The No. 234 character "rw-" represents the permissions of the currently owned user. So the value is expressed as 4+2=6

The No. 567 character "rw-" represents the permissions for the group that is currently owned. So the value is expressed as 4+2=6

The No. 890 character "r--" represents other user rights. So the value is represented as 2

So the permission to manipulate this file is represented by a value of 662

Change permissions

sudo chmod [u belongs to user g belongs to group O Other User a All users] [+ Increase permissions-reduce permissions] [r W x] directory name

For example: There is a file filename, the permission is "-rw-r----x", the permission value is changed to "-rwxrw-r-x", with a numeric representation of 765

sudo chmod u+x g+w o+r filename

The above example can be represented by a numerical value

sudo chmod 765 filename

Linux Common operating instructions (for interview purpose)