Basic commands

List of Basic Commands in Unix

#  --> root user prompt.

$  -->  user working prompt.

$ log name  --> displays current user name.

$ pwd  -->  present working directory.

$ date  -->  Display current date & time.

$cal  -->  Displays current month calendar.

$cal 2020  --> particular year total months.

$cal 04 2020  -->  2020 year 04th month calendar.

$who  -->  To display the information about all the users who have logged into the system.

$ who am i  -->  It displays current user name.

$ finger  -->  It displays complete information about all the users who are logged in.

$ uptime  -->  How log server up & running, how many users connected and load avg time.

 

$ which (Or)  $ wher    -->    Given command location

EX: Which date

 

$tty    -->     Terminal position.

$df      -->    Displays disk free size

$du      -->    Disk usage information

$clear    -->     To clear the screen

 

Creating files:

  • Cat (concatenate): It is used to create a file and display, appending the contents of a file
  • To create a file:

$Cat>filename

Hello world

Ctrl+D (To save the file)

  • To Display the content of the files:

$cat<filename

(or)

$cat filename

 

  • To append the data in the existing file:

$cat >>filename

-------------------------

-------------------------

Ctrl +D (To save)

 

  • Touch: To create multiple files but all are empty.

Syn:  $touch file1 file2 file3 ……………..filen

               Ex: $touch file1 file2 file3

  • Ls: Displays the contents of a directory.

 

Options:

-    r    -->Reverse

-   i    -->inode

 -a  --> hidden

 -   l  --> long list

-R    -->Recursively

-   h  --> human readable

 

Mkdr: Creates a directory.

Syn:  mkdir <Dirname>

$mkdir linux

  • To create multiple directories:

$ mkdir dir1 dir2 dir3 -----------------dirn

  • To create a nested directory:

$ mkdir –P world/asia/india/ap/hyd

Parent

  • To check: $ tree world

(or)

$   ls – R

  • Navigation commands:

Cd:  Changes the current location.

Cd.. --->To go one level back

cd../.. ---> To go two levels back

cd --->To change user’s home directory.

EX: $ cd world

$ ls

Note:  The trailing slash (1) is optional when you’re using the cd command. It indicates that the name being specified is a directory.

EX:  $cd Documents/

  • CP: Copies files or directories form one location to another.

Syn: CP [options] source destination

--- R   --->  copies recursively

--- f     ---> Copies forcefully

--- V  --->  provides verbose output

 

EX:       $ CP file1 file2   ------------>  one file to another.

$CP file1 file2 Documents   ------------>   Multiple files into directory.

$CP  -R Documents unix ------------>one directory to another.

$ CP –rvf Documents unix world/asia/india/ap/hyd

$ CP /var/log/messags ------------>  (.) represents current location.

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  • MV: Moves or renames files and directories.

Syn:   mv [options} SOURCE DEST

--- V   --> verbose

  • Rename the file by specifying the file name & new name of the files

Mv messages messages.bak

 

  • Move it to the test directory for safe keeping:

Mv messages. Bak test/

$ls test

  • Rm: Deletes files or directories

Syn:  rm [options} FILE

---    i  ---> interactive

---   r ---> Recursively

---   f  ---> Forcefully

  • Delete the messages.bak file:

$cd test

$rm   - I  messages. Bak

  • Delete the test directory:

$ cd ..

$ rm  - rf test/

  • File: Displays the type of a file

Syn:  file <file name>

Ex:  $ file test1

Test1: empty

$ file /etc/passwd

Password : ASCII test.

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