Unix basic commands :

1. $ LOGNAME : It displays the current user information

2. $PWD : present working directory

3. $DATE : It displays the system date & time

4. $clear : To clear the screen

5. $cal : it current month and year

6. $cal 2000 : Displays the 2000 year calendar

7. $cal 8 2006 : displays the 8th

month of 2006

8. $exit or logout : exit from current user account

9. $ who : displays the all user in who are currently working on server

10. $finger : displays the all user who are currently working on

server with more information.

11. Who am I : displays current user information

12. Which or where : displays the location of the given command

Syn: $which pwd

13. Cat : is use to create new files or to open exiting files or to

append data to the exiting files.

Syn: cat >filename

Redirect : cat file1 file2 file3 >file4.

Append : cat >>filenamesingle file.

Multi files : cat file1 file2 file3 >>kiran.

Open file : cat <filename.

Open multi files : cat file1, file2, file3.

14. Touch : It is used to create an empty file i.e. 0 byte file

SYN: $ touch filename

create multiple files : touch file1 file2 file3

15. rm : deleting files or directories

rm filename : deleting single file

rm -i filename : deleting files with confirmation

rm file1 file2 : deleting multiple file

rmdir dirname : deleting the directory but the directory must be empty

rm -r dirname: deleting directory recursively.

rm –ri dirname : remove directory with confirmation

rm * : it delets all files.

16. mkdir : creating directories

Syn: $mkdir dirname

$Mkdir .dirname : hidden directory.

17. Cd : change directory

Sys: $cd abc

cd ..: to come out from current directory

cd ../..: parent directory

cd/ : it changes to root directory

cd ~ : it changes to home directory.

18. cp : copy source file to target file.

SYN : Cp emp1 emp2

19. mv : it is used to rename or move file

Ex : mv exiting filename new filename

Mv emp .empt : to hide

Mv .emp emp : to unhide

20. ls : display, list of all files & directories in a current direc-tory

21. ls|more : display, list of all files & directories page by page

22. ls –a : display, list of all files & directories including hidden files

23. ls –r : display list of all files & directories revers order in a

current directory.

24. Ls –t : display list of all files & directories according to date.

25. cmp : it compares two files char by char

Sys: cmp file1 file2

26. comm. : It display common lines b/w 2 files

Syn: Comm File1 file2

27. diff : it display different lines b/w 2 files

syn: diff file1 file2

28. pg : it display the file contents page by page

Syn: $Pg filename

29. more : it also display the file contents page by page

Syn: $more filename

30. head : it display the 1st

n lines from the file

Sys: $ head –n filename

31. tail : it display the last n lines from file

Syn: $ tail –n filename

32. wc : it counts the no of lines, words, chars in a given file.

Syn: $wc filename

i) wc –l filename : it gives the no of lines in a given file

ii) wc –w filename : it gives the no of words in a given file

III) wc –c filename : it gives no. of char in file

iv) wc -lw filename : it gives the no of lines and character in a given file.

33.grep : Is used for to search a string or regular expression

in a given file(s).

Eg : i) $ grep kiran sample

ii) $grep kiran a1, a2, a3:

1. $ grep kiran * it searches for kiran in

current dir files (all files).

$grep “kiran raja” sample : it searches for more than one word

grep cmd options.$ grep –i kiran sample : ignore case sensitive

$ grep –c raja sample : count no of lines

$grep –n kumar sample : print along with the line numbers

34. Sed : to replace a string

Ex:$ sed “s/existing string/new string/g” filename : sed is used to find and replace

the stirng.

Ex) $sed “s/Unix/Linux/g “ kiran

35. Cut : it is used for to retrieve required fields and

characters from a given file

Ex: madhav is good boy :18 chars

Cut –f 2-5 madhav : o/p= adha

Cut –c 1-10 madhav

Cut –c 5-10, 15-20 madhav : for every line 5-10, 15-20 characters

36. Sort : it is used for to sort the file content. By default it

sorts file contents based on ASCII values-default

is ascending.

syn: $ Sort sample

i) sort –r sample : displays descending order

ii) sort –u sample : it displays unique lines in the given file

37. Uniq : it displays unique lines in the given file but the file

contents should be in sort order.

Syn: i) $ uniq filename

ii) $ uniq -u filename : it eliminate the duplicates.

iii) $ Uniq –d filename : displays only duplicated lines

iv) uniq –c filename : it counts how many times lines duplicated.

38. chmod : it is used for to change file permissions

Syn: $ chmod

i) ls –l filename : rw- rw- r—

ii) chmod g+x filename : rw- rwx r—

iii) chmod u+x, g-w filename : rwx r-x r—

Octal code

Read------4

Write-----2

Execute—1

iv) $chmod 756 filename : rwx r-x rw-

v) $chmod 642 filename : rw- r-- -w-

39. ftp : file transfer protocol -----transfer files from

one server to another

Steps:

$ ftp ipaddress

Login: -------

Password: ------

Ftp>ls (server)

Ftp>|ls(client)

Ftp>get filename (to download a file)

Ftp>mget file1 file2----- (to download multi files)

Ftp>put filename (to upload a file)

Ftp>mput file1 file2----- (to upload multi files)