commands.html

Linux Command Prompt

Basic Linux Commands : without which you can't survive in technical world!!!

1) ls -- to list files and directories
    Examples:    ls Mail, ls -a
                      ls -l /usr/bin
    Options: -l, -a

2) cd -- Type cd followed by the name of a directory to access that directory.
    Examples:   cd games, cd ..
    Imp: "cd -" will get you in the last working directory

3) pico -- To create or edit a file
Examples:   pico myfile.txt, pico

4) vim -- Advance text editor
    Example:   vim myfile.txt
    To learn basic vim, visit: http://www.dynamic-apps.com/linux_vim.jsp

5) chmod -- change file access permissions
    Example:   chmod -R 753 games

Permissions	alias	weightage
read	r	4
write	w	2
execute	x	1

In 753, the first 7 (1st letter) represents the permissions to himself,
                          5 (2nd letter) represents the permissions to group.
                          3 (3rd letter) represents the permissions to others.

Options:    -R for whole directory
                      7=4+2+1 ; 5=4+1; 3=2+1

6) pwd -- shows the "present working directory"

7) cp -- copy the files/diectories
    Examples:    cp oldfile.txt newfile.txt
                         cp -R olddir newdir
    Options: -R for copying complete directory

8) mv -- move or rename the file/directory
    Examples:    mv oldfile.txt newfile.txt
                         mv olddir newdir

9) rm -- remove files/directory
    Examples:   rm file1.txt
    Options:     -r deletes whole directory
                         -f deletes without asking confirmation

10) mkdir -- make a new directory
    Examples:    mkdir games

11) rmdir -- deletes a (empty) directory
    Examples:    rmdir games

12) man -- show the manual pages
    Examples:    man mkdir
                         man man

13) date -- show date and time

14) cal -- show calendar

15) du -- show file space usage
     Examples:    du -hs games; du ; du movie.dat
     Options: -h print sizes in human readable format(e.g., 1K 234M 2G)
                    -s display only a total for each argument

16) passwd -- to change passwd

17) pine -- to check mails

18) logout -- make you exit

More Basic Commands -- without which you can't survive in IITB!!!

1) tin -- to check newsgroups

2) telnet -- to login into other computer/server
    Example: telnet 10.107.1.2
    Imp: Try command 'rlogin'

3) ssh -- secure login into other computer/server
    Example: ssh [email protected]

4) finger -- look for information about users logged on server
    Example: finger; finger agoyal

5) talk -- talk to other user
    Example: talk agoyal

6) w -- Show who is logged on and what they are doing

7) write -- write to other users
    Example: write agoyal

8) ftp -- to transfer files from one computer to another
    Example: ftp 10.105.1.11
    Use 'gftp' for graphical interface

9) cat -- print the file(s) on standard output
    Example: cat myfile.txt
    Imp: Try commands 'head', 'tail', 'less', 'more'

10) alias -- alias a command
    Example: alias rm='ls'

Advance Commands -- without knowing which you can't be called "STUD"

1) df -- show harddisk partitions
    Example: df -h

2) locate -- locate a file containing some expression
    Example: locate games

3) grep -- print lines matching a pattern
    Example: locate games|grep nfs

4) find -- search for files in a directory hierarchy
    Example: find . -name filename -print

5) ps -- report process status
    Examples: ps; ps -aux

6) top -- display Linux tasks

7) kill, killall -- kills a process
    Examples: kill -9 1290; killall -9 mplayer
    Here -9 is an option to kill a process completely. 1290 is a process ID (PID).

8) tar -- compress/uncompress files/directories
    Examples: tar -xvf file.tar -- uncompress a file 'file.tar'
                        tar -xzvf file.tar.gz -- uncompress a file 'file.tar.gz'
                        tar -xjvf file.tar.bz2 -- uncompress a file 'ffile.tar.bz2'
                      tar -cvf file.tar file -- compress the file 'file' to 'file.tar'
                        tar -czvf file.tar.gz file -- compress the fille 'file' to file.tar.gz
                        tar -cjvf file.tar.bz2 file -- compress the fiile 'file' to file.tar.bz2

9) file -- determine file type

Some More fundaes: for cool dudes

1) How to open graphical applications from other computer?
Suppose you are sitting on comp 'A' with ip 10.8.1.82. You want to open an graphical application on comp 'B' with ip 10.8.1.22. Do the following:
    a) type "xhost +" on comp 'A'
    b) login to comp 'B' via 'ssh' or 'telnet'
    c) type "export DISPLAY=10.8.1.82:0.0" on command prompt of comp 'B'
    d) open the application. e.g. 'gftp'

2) Use <TAB> for the command completion

3) Don’t waste time and energy retyping commands at the prompt. Instead, use the ! option. To automatically re-display the last command you typed at the prompt, type: !! and press enter. Press again to invoke the command. You can also automatically re-display a command you typed earlier by using the ! and the first few letters of the command.
Ex: At the Linux prompt you had typed the command clear, followed by the command pico, followed by the command ftp. In order to re-display the clear command you type: !cl and press enter. In order to re-display the last command you typed, simply type: !! . Try it out. You’ll find this a time saver when dealing with long commands. Especially commands like tar!

4) You can also use reverse search for retyping commands. e.g. type "Ctrl+r", and then type few letters of command. It will display the command.

Common Softwares in Linux

Some common softwares you will need:
1) gaim -- Instant Messenger like yahoo and msn messenger.
2) mplayer -- Movie Player like Windows Media Player in Windows.
3) xmms -- Play Songs like winamp in Windows.
4) openoffice -- Run Office Application like officexp, office2k3 in Windows.
5) mozilla -- To browse internet like Internet Explorer in Windows.
6) gftp -- for transfering files.
7) gimp -- for creating/editing pictures.

See the complete Linux Windows Equivalence Table here.

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