EX. NO.

1 AIM:

BASIC UNIX COMMANDS

To study basic unix commands. DISPLAY COMMANDS a) date used to check the date and time syn: $ date
Format +%m +%h +%d +%y +%H +%M +%S Purpose To display only month To display month name To display day of month To display last two digits of the year To display hours To display minutes To display seconds Example $ date + % m $ date + % h $ date + % d $ date + % y $ date + % H $ date + % M $ date + % S Result 06 June O1 09 10 45 55

b) cal used to display the calendar syn: $ cal 2 2009 c) echo used to print the message on the screen. Syn: $ echo text d) ls used to list the files. Your files are kept in a directory. Syn: $ ls
ls s ls l ls t ls u ls s ls r ls f All files (include files with . prefix) Long detail (provide file statistics) Order by creation time Sort by access time (or show when last accessed together with l) Order by size Reverse order Mark directories with / ,executable with * , symbolic links with @ , local sockets with = , named pipes (FIFOs) with | ls s Show file size ls h Human Readable, show file size in Kilo Bytes & Mega Bytes (h can be used together with l or -s) ls [a-m]* List all the files whose name begin with alphabets From a to m ls [a]* List all the files whose name begins with a or A

Eg: $ ls > mylist Output of ls command is stored to disk file named my list e) lp used to take printouts syn: $ lp filename

f) man used to provide manual help on every UNIX commands. Syn: $ man unixcommand $ man cat g) who & who am i it displays data about all users who have logged in to the system currently. The next command displays about current user only. Syn: $ who $ who am i h) uptime tells you how long the computer has been running since its last reboot or power-off. Syn: $ uptime i) uname it displays the system information such as hardware platform, system name and processor, OS type. Syn: $ uname a j) hostname displays and set system host name syn: $ hostname k) bc stands for best calcualtor
$ bc 10/2*3 15 Quit $ bc scale =1 2.25+1 3.35 quit $ bc ibase = 2 obase = 16 11010011 89275 1010 Quit $ bc sqrt(196) 14

$ bc for (i=1;i<3;i=i+1)I 1 2 3 Quit

$ bc-l scale = 2 s(3.14) 0

Result: Thus the display commands were executed successfully.

2. FILE MANIPULATION COMMANDS a) cat this create, view and concatenate files. Creation: Syn: $ cat > filename Viewing: Syn: $ cat filename Add text to an existing file: Syn: $ cat >> filename Concatenate: Syn: $ cat file1 file2 > file3 $ cat file1 file2 >> file3 (no overwriting of file3) b) grep used to search a particular word or pattern related to that word from the file. Syn: $ grep searchword filename Eg: $ grep anu student c) rm deletes a file from the file system syn: $ rm filename d) touch used to create a blank file. Syn: $ touch file names e) cp copies the files or directories syn: $ cp source file destination file eg: $ cp student stud f) mv to rename the file or directory syn: $ mv old file new file Eg: $ mv i student student list (-i prompt when overwrite)

g) cut it cuts or pick up a given number of character or fields of the file. Syn: $ cut <option> <filename> Eg: $ cut c filename $ cut c 1 -10 emp $ cut f 3,6 emp. $ cut f 3-6 emp -c cutting columns -f cutting fields h) head displays 10 lines from the head (top) of a given file syn: $ head filename eg: $ head student To display the top two lines: $ head -2 student i) tail displays last 10 lines of the file syn: $ tail filename eg: $ tail student To display the bottom two lines; $ tail -2 student j) chmod used to change the permissions of a file or directory. Syn: $ chmod category operation permission file Where, category is the user type Operation is used to assign or remove permission Permission is the type of permission File are used to assign or remove permission
a) Category ------------b) Operation -------------c) Permission -------------a) u users g group o others a all ------------------b) + assign - remove = assign absolutely -------------------c)

r read w write x- execute ------------------------

Examples: $ chmod u-wx student removes write and execute permission for users $ chmod u+rw, g+rw student assigns read and write permission for users and groups $ chmod g=rwx student assigns absolute permission for groups of all read, write and execute permissions k) wc it counts the number of lines, words, character in a specified file(s) with the options as l, -w, -c syn: $wc l filename $wc w filename $wc c filename

Result: Thus the file manipulating commands were executed successfully

3. DIRECTORY COMMANDS a) mkdir used for creating a directory. Syn: $ mkdir <directory name> b) rmdir it is an utility for deleting empty directories. Syn: $ rmdir directory name c) cd changes the current directory of the shell. Syn: $ cd ~ (stores the path to your home directory) $ cd.. (changes to parent directory) $ cd d) pwd (Print Working Directory) shows the current directory. Syn: $ pwd

Result: Thus the directory commands were executed successfully

4. PROCESS COMMANDS a) exit terminates a process syn: $ exit b) kill terminates or send a signal to process syn: $ kill c) passwd create or change a password syn: $ passwd d) telnet connect to remote machine using the telnet protocol syn: $ telnet

Result: Thus the process commands were executed successfully.

5. GROUPING COMMANDS a) The semicolon (;) - used ot execute more than one command at a time eg: $ who ; date ; ls b) The && operator signifies the logical AND operation. It means that only if first command is successfully executed, then the nest command will be executed. Eg: $ ls marks && date c) The || operator signifies the logical OR operation. It means the first command will happen to be unsuccessful, it will continue to execute next command. Eg: $ ls marks || date

Result: Thus the grouping commands were executed successfully