Basic Linux Knowledge

Basic commands under Linux

ls : List

pwd : Print work directory (printing working directories)

CD : Change directory (switch directory)

Example: CD-Back to last directory

Example: cd ~ Back to the current user directory

Example: CD. /: Back to the top level directory of the current directory

Clear : Clear screen

mkdir : New directory

rmdir : Delete Empty directory

Cat : View file contents

Touch : Create a file

RM : Delete

cp : Copy

file : View Properties

MV : Move, rename

echo : Writing content to a file

Example: Echo Hello > A writes "Hello" content to a file (overwriting the previous content in a file)

echo OK >> A append write "OK" to a file (not overwritten)

Second, Linux under the Ten classic commands

tar : (Xx.tar, xx.tar.gz)

Package Example: TAR-CF H.tar OK to package the files under the OK directory as H.tar

Example: TAR-CVF h2.tar OK to package files under the OK directory as H2.tar plus v parameter to see package details

Unpacking Example: TAR-XVF H2.tar the H2.tar package to unpack the x parameter as the unpacking parameter

Package and compress (current directory) Example: TAR-CZVF h3.tar.gz OK to package and compress the files in the OK directory to H3.tar plus the z parameter for packaging

Unpack and decompress (current directory) Example: TAR-XZVF h3.tar.gz Unpack the h3.tar.gz package x parameter as the unpacking parameter

Unpack and unzip (other directories) Example: TAR-XZVF h3.tar.gz-c/Unpack the h3.tar.gz package into the "/" directory C (uppercase) parameter to change the path

Multiple directory Packaging Compression example: TAR-CZVF h4.tgz OK Test test2 package The file under the OK directory and compress it to h4.tar with the Z parameter as the package

Note: Suffixes can be customized, not necessarily xx.tar.gz or abbreviated to XX.TGZ but it is best to use defined definitions

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chmod(change mode):

#ls-L (can be simply written as "ll")

-rw-r--r--1 root root 03-16 14:30 a

-rw-r--r--1 root root 10240 03-16 14:38 H2.tar

Drwxr-xr-x 2 root root 4096 03-16 14:28 OK

Drwxr-xr-x 2 root root 4096 03-16 14:28 test

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Interpretation:-rw-r--r--

-Type ("-" stands for file, "D" stands for directory)

rw-the creator's permission to manipulate the file ("R" Readable, "w" Writable, "x" executable)

r--user permissions to the file ("R" Readable, "w" Writable, "x" executable) for the same group as the creator

r--user permissions for files with different groups of creators ("R" Readable, "w" Writable, "x" executable)

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RWX rwx rwx Maximum Privileges

In binary notation: 111 111 111

Represented by numbers: 777 each set of permission levels can be represented by an octal number

---------minimum permissions

Represented by numbers: 000

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chmod usage

Example 1:-rw-r--r--1 root root 03-16 14:30 a

#chmod U+x A gives the creator "executable" permission to file a

???? Note: U (user): Represents creator G (group): Representative Group O (Other): Represents different Group A (all): On behalf of all users

???? -rwxr--r--1 root root 03-16 14:30 a

Example 2: #chmod a=x A gives all users only executable permissions

---x--x--x 1 root root 03-16 14:30 a

Example 3: #chmod 777 A gives all users the highest privileges

-rwxrwxrwx 1 root root 03-16 14:30 a

Summarize

chmod u/g/o/a (+/-/=) r/w/x FileName

chmod three octal numbers filename

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Not to be continued ...

Basic Linux Knowledge