Linux Commands

Linux Commands (UBUNTU)

Ubuntu Acess through terminal

How to access Terminal

Terminal will be under Applications menu -> Accessories -> Terminal

Or

you can access it with shortcut key ctrl+alt+T

iiitmk@iiitmk-HP-Compaq-6200-Pro-SFF-PC:~$

The first information that you see in the command line is your username which is iiitmk in my case ,

@iiitmk-HP-Compaq-6200-Pro-SFF-PC is the name of the computer.

After that information The ~ sign denotes the home which is same location as you go in the

place>>>home. $sign is a symbol for regular user that means you are login as regular user not the root user.

The full information is like this in my ubuntu: iiitmk@iiitmk-HP-Compaq-6200-Pro-SFF-PC:~$

(The root user in GNU/Linux is the user which has administrative access to your system. Normal users do not have this access for security reasons, administrative access is given to individual users, who may use the "sudo" application to perform administrative tasks. The first user account you created on your system during installation will, by default, have access to sudo. When you run an application that requires root privileges, sudo will ask you to input your normal user password.

To use sudo when using the command line, simply type "sudo" before the command you wish to run. Sudo will then prompt you for your password.

Note: Be careful when doing administrative tasks, you might damage your system! )

Changing directory

The cd command changes directories. When you open a terminal you will be in your home directory. To move around the file system you will use cd.

iiitmk@iiitmk-HP-Compaq-6200-Pro-SFF-PC:~$ cd Desktop/

iiitmk@iiitmk-HP-Compaq-6200-Pro-SFF-PC:~/Desktop$

To navigate into the root directory, type: cd /

To navigate up one directory level, type: cd ..

To navigate to the previous directory (or back), type: cd -

pwd - The pwd command outputs which directory you are currently located in

iiitmk@iiitmk-HP-Compaq-6200-Pro-SFF-PC:~/Desktop$ pwd

/home/iiitmk/Desktop

.(A single dot) The current directory

..(Two dots) The directory above the current directory

~(Tilde) A reference to a user directory under /home. For example ~fredb would point to /home/fredb

Listing the file and directory

ls

The ls command outputs a list of the files in the current directory

iiitmk@iiitmk-HP-Compaq-6200-Pro-SFF-PC:~$ ls

Desktop Downloads Music Public Videos

Documents examples.desktop Pictures Templates

Copying a file

cp

The cp command makes a copy of a file. For example, type:

iiitmk@iiitmk-HP-Compaq-6200-Pro-SFF-PC:~/Desktop$ cp newfile.txt copyfile.txt

iiitmk@iiitmk-HP-Compaq-6200-Pro-SFF-PC:~/Desktop$

Moving a file to another location

mv

The mv command moves a file to a different location or will rename a file. Examples are as follows:

iiitmk@iiitmk-HP-Compaq-6200-Pro-SFF-PC:~/Desktop$ mv copyfile.txt test/

Renaming a file via terminal (same command is used)

iiitmk@iiitmk-HP-Compaq-6200-Pro-SFF-PC:~/Desktop$ mv newfile.txt rename.txt

=============================================================

Creating a new folder:

mkdir

iiitmk@iiitmk-HP-Compaq-6200-Pro-SFF-PC:~/Desktop$ mkdir umesh

Creating a file

touch

iiitmk@iiitmk-HP-Compaq-6200-Pro-SFF-PC:~/Desktop$ touch newfile.txt

iiitmk@iiitmk-HP-Compaq-6200-Pro-SFF-PC:~/Desktop$

To view the text file

less

iiitmk@iiitmk-HP-Compaq-6200-Pro-SFF-PC:~/Desktop$ less UBUNTU_commands

========================================================

to delete files

rm

iiitmk@iiitmk-HP-Compaq-6200-Pro-SFF-PC:~/Desktop$ rm rename.txt

Remove a Directory (empty Duirectory )

iiitmk@iiitmk-HP-Compaq-6200-Pro-SFF-PC:~/Desktop$ rmdir 123

Remove a Directory with all files

iiitmk@iiitmk-HP-Compaq-6200-Pro-SFF-PC:/var/lib/tomcat6/webapps$ sudo rm -rf test2

======================================================

Linux or ubuntu Directory structure

In the Linux operating system, all filesystems are contained within one directory hierarchy. The root directory is the top level directory, and all its subdirectories make up the directory hierarchy. This differs to other operating systems such as MS-Windows which applies a separate hierarchy for each device and partition.

iiitmk@iiitmk-HP-Compaq-6200-Pro-SFF-PC:/$ ls

bin dev initrd.img lost+found opt sbin sys var

boot etc lib media proc selinux tmp vmlinuz

cdrom home lib64 mnt root srv usr

/bin - binary applications (most of your executable files)

/boot - files required to boot (such as the kernel, etc)

/dev - your devices (everything from drives to displays)

/etc - just about every configuration file for your system

/home - locally stored user files and folders

/lib - system libraries (similar to Program Files)

/lost+found - lost and found for lost files

/media - mounted (or loaded) devices such as cdroms, digital cameras, etc.

/mnt - mounted file systems

/opt - location for optionally installed programs

/proc - dynamic directory including information about and listing of processes

/root - home folder for the root user

/sbin - system-only binaries (see /bin)

/sys - contains information about the system

/tmp - temporary files

/usr - applications mainly for regular users

/var - mainly logs, databases, etc.

/usr/local/bin - the place to put your own programs. They will not be overwritten with upgrades.

/usr/share/doc - documentation.