Sandhya.np14 at 11:38, 8 March 2015

2015-03-08T11:38:24Z

Show changes

Pratik kamble at 11:16, 9 July 2014

2014-07-09T11:16:59Z

Pratik kamble at 11:16, 9 July 2014

2014-07-09T11:16:43Z

Show changes

Minal: Created page with '{| border=1 !Time !Narration |- |0:00 |Dear friends, welcome to a spoken tutorial on the Linux Operating System. |- |0:05 |In this tutorial, we will study some basic commands. …'

2012-12-28T09:30:52Z

Created page with '{| border=1 !Time !Narration |- |0:00 |Dear friends, welcome to a spoken tutorial on the Linux Operating System. |- |0:05 |In this tutorial, we will study some basic commands. …'

New page

{| border=1
!Time
!Narration
|-
|0:00
|Dear friends, welcome to a spoken tutorial on the Linux Operating System.
|-
|0:05
|In this tutorial, we will study some basic commands.
|-
|0:10
|I am using Ubuntu 10.04.
|-
|0:12
|We assume that you know how to get started with the Linux operating system.
|-
|0:17
|If you are interested, it is available through another spoken tutorial, on the website [http://spoken-tutorial.org/ http://spoken-tutorial.org].
|-
|0:26
|In this tutorial, we will see what are commands and what is a command interpreter.
|-
|0:33
|Then we will learn about how to find help in Linux using the man command.
|-
|0:39
|Now the first question is, "what are commands?".
|-
|0:43
|In simplest terms we can say that Linux commands are words that when keyed in cause some actions to take place.
|-
|0:52
|Linux commands are seldom more than four character in length like ls, who, ps etc.
|-
|0:59
|The commands are in lower case and they are case sensitive. Let us see an example .
|-
|1:05
|Go to the applications menu.
|-
|1:08
|Select accessories and then click on terminal from the available options
|-
|1:14
|or press ctrl alt t on your keyboard to open a terminal window.
|-
|1:20
|Now we can see a prompt ($) and a cursor blinking next to it. This is where we need to type in a command.
|-
|1:29
|Type in the words who and press enter.
|-
|1:34
|We can see the name of the users logged in. Actually we have just executed a command called who which shows who are logged into the system.
|-
|1:47
|But which entity is converting these commands which are nothing more than a few letters into actions?
|-
|1:54
|This is the job of the Command Interpreter, also called the shell.
|-
|1:59
|We can define a shell as a program that acts as the interface between us and the Linux system,
|-
|2:08
|allowing us to enter commands for the operating system to execute.
|-
|2:13
|On Linux it’s quite feasible to have multiple shells installed, with different users able to pick the one they prefer.
|-
|2:22
|On Linux, the standard shell that is always installed as /bin/sh is called bash, the GNU Bourne-Again SHell, from the GNU suite of tools.
|-
|2:35
|The commands we would be covering in this tutorial are generic and can run on most of the Linux shells with slight variations.
|-
|2:44
|Nevertheless, we would be using the bash as the shell for demonstration in this tutorial.
|-
|2:51
|It is because bash is the most popular shell and portable to almost all UNIX.
|-
|2:58
|Other shells include the Bourne shell which is the original Unix shell, C Shell and Korn shell
|-
|3:08
|To see which shell we are using
|-
|3:11
|go to the terminal and type the command echo space dollar in capital SHELL and press enter
|-
|3:27
|Normally the output is /bin/bash which gives us the bash shell.
|-
|3:34
|There are ways by which we can activate different shells. Those will be covered in an advanced tutorial.
|-
|3:42
|Commands are actually files containing programs, often written in C.
|-
|3:47
|These files are contained in directories. To find out where a command is stored, we can use the type command.
|-
|3:55
| Type at the command prompt. Type--space-- ps and press enter.
|-
|4:03
|This shows that ps is actually a file stored in the /bin directory.
|-
|4:09
|When we key in a command at the command prompt, the shell searches for a file matching the command name in a list of directories.
|-
|4:18
|If it is found, then the program corresponding to that file is executed, else a “command not found” error is given.
|-
|4:27
|The list of directories searched is specified by the PATH variable, as we will see later.
|-
|4:34
|For now, if we want to see this list, just type the command echo space dollar PATH
|-
|4:44
|in capital and press enter
|-
|4:52
|Talking of commands, there is one important thing that we need to know.
|-
|4:57
|Linux commands are of two types: External commands and internal commands.
|-
|5:02
|Now external commands are those which exist as separate files/programs.
|-
|5:07
|Most commands in Linux are of this nature. But there are some commands whose implementation is written within the shell and they do not exist as separate files.
|-
|5:18
|These are internal commands.
|-
|5:20
|The echo command, which we will see later, is in fact an internal command.
|-
|5:25
|Go to the terminal and type at the command,
|-
|5:33
|type space echo and press enter.
|-
|5:40
|The output shows echo as a shell built-in.
|-
|5:43
|So instead of giving a file name it shows that the echo command's implementation is internal to the shell. So it is called internal command.
|-
|5:56
|Another important thing which we need to understand is the structure of commands.
|-
|6:01
|Commands can be of one word or multiple words, separated by white spaces.
|-
|6:08
|In the second case the first word is the actual name of the command while the other words are the arguments.
|-
|6:16
|Arguments can be options or expressions or file names.
|-
|6:20
|A command can perform different tasks depending on the option specified.
|-
|6:26
|They are generally preceded by a single or double minus sign(-), called short and long option, respectively.
|-
|6:35
|Go to the terminal window and type the commands and see their outputs.
|-
|6:40
|Type clear to clear the terminal window
|-
|6:44
|Then type ls and press enter
|-
|6:49
|Again, type clear and press enter
|-
|6:55
|Type ls space minus a and enter.
|-
|7:04
|Type clear to clear the terminal window
|-
|7:11
|Now type ls space minus minus all and press enter.
|-
|7:19
|Again, type clear to clear the terminal .
|-
|7:23
|Now type ls space minus d and press enter.
|-
|7:32
|At this point it is enough to understand how the command's behavior changes with change of options
|-
|7:40
|In Linux we have a larger number of commands,
|-
|7:45
|each of which have many different options.
|-
|7:48
|Commands can also be combined together as we will see later. So how do we keep so much in mind?
|-
|7:55
|In reality you don't have to. This is because of the excellent online help facility available in Linux.
|-
|8:01
|The man command provides documentation on just about every available command on the system.
|-
|8:08
|For instance, to know about say, the ls command, all you have to do is to go to the terminal
|-
|8:16
|and type man command with ls as argument that is type man space ls and press enter
|-
|8:30
|Press q to come out.
|-
|8:35
|man is the system’s manual pager. Each argument given to man is normally the name of a program, utility or function.
|-
|8:43
|The manual page associated with each of these arguments is then found and displayed.
|-
|8:49
|A section, if provided, will direct man to look only in that section of the manual.
|-
|8:55
|The default is to search in all of the available sections, following a pre-defined order and to show only the first page found, even if page exists in several sections.
|-
|9:07
|You can use man command to know more about the command man itself.
|-
|9:14
|Go to the terminal and type man space man and press enter.
|-
|9:23
|Press q to come out of it.
|-
|9:26
|man command has many options.
|-
|9:30
|Here let me tell the most useful ones. Sometimes we know what we want to do but do not know the exact command. Then what can we do?
|-
|9:41
|man provides the -k option which takes a keyword and return a list of commands and their brief purpose.
|-
|9:50
|For example, create a directory, we may not know the exact command,
|-
|9:56
| so we can go to the command prompt and type man space minus k space directories and press enter.
|-
|10:12
|Now we can search each of these commands to see what we actually need.
|-
|10:17
|The same thing can be achieved using apropos command.
|-
|10:21
|Type at the command prompt apropos space directories and press enter to see the output.
|-
|10:36
|Some times we do not need too much details. We only need to know what a command does.
|-
|10:40
|In that case we can use the whatis command or man -f. Both give one line description about the command.
|-
|10:52
|Go to the terminal type clear to clear the terminal window
|-
|10:58
|now type whatis space ls and press enter
|-
|11:06
|Some commands have many options. We may want to obtain a list of the different options that a command has.
|-
|11:13
|Then we use the minus help option.
|-
|11:18
|Go to the command prompt and type ls space minus minus help and press enter
|-
|11:29
|I will scroll up so that u can see all the options on this manual page
|-
|11:45
|Thats it for this part of the Linux Spoken tutorial. Spoken Tutorials are a part of the Talk to a Teacher project, supported by the National Mission on Education through ICT.
|-
|11:56
|More information on the same is available at the following link .
|-
|12:00
| This script has been contributed by ----------------------(name of the translator) and this is -----------------------(name of the recorder) from --------------------------(name of the place)signing off. Good bye

|}

@@ Line 1: / Line 1: @@
 {| border=1
-|Time
+|'''Time'''
-|Narration
+|'''Narration'''
 |-
 |00:00

Linux/C2/Basic-Commands/English-timed - Revision history

Sandhya.np14 at 11:38, 8 March 2015

Pratik kamble at 11:16, 9 July 2014

Pratik kamble at 11:16, 9 July 2014

Minal: Created page with '{| border=1 !Time !Narration |- |0:00 |Dear friends, welcome to a spoken tutorial on the Linux Operating System. |- |0:05 |In this tutorial, we will study some basic commands. …'