Linux/C2/Basics-of-System-Administration/English-timed

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Linux – Basics of System Administration


Time
Narration
00:02 Hello and welcome to the Spoken Tutorial on Basics of System Administration in Linux.
00:09 In this tutorial we will learn the followings.
00:13 adduser
00:14 su
00:16 usermod
00:17 userdel
00:18 id
00:19 du
00:20 df
00:22 I am using Ubuntu 10.10 for this tutorial.
00:27 As a prerequisite please go through the spoken tutorial on “General Purpose Utilities in Linux”
00:35 which is available on this website
00:39 One must have admin access in order to execute the commands shown.
00:47 Let us first learn how to create a new user.
00:53 The “adduser” command will create a new user login for us along with authentication.
01:01 We can add any user account with the help of “sudo” command.
01:06 Let me give you a brief explanation about the “sudo” command.
01:11 Sudo command allows the administrative user to execute a command as a super user.
01:19 The sudo command has many options. We will learn about the options as we go further in this tutorial.
01:27 Lets now learn how to create a “New User”.
01:32 Open the “Terminal” by pressing the keys “Ctrl, Alt and t” simultaniously on your keyboard
01:45 I have already invoked the “Terminal” here.
01:49 Here type the command “sudo space adduser” and press Enter.
01:58 You will be prompted for a password.
02:01 I will give the “Admin” password here and Enter.
02:07 The typed password on the terminal, is not visible.
02:11 So we have to type the password carefully.
02:16 Once done, a message “adduser : Only one or two names allowed” is displayed.
02:27 So let us create a new user account named “duck”.
02:34 Type the command :
02:36 sudo space adduser space duck, and press Enter.
02:45 We have created a new user called “duck”.
02:49 In the process of creating a new user, a seperate “home” directory for that user has also been created.
02:58 Please note that we will be prompted for a new password for the user “duck”.
03:05 Type the password of your choice, in my case im going to type “duck” as the password and press Enter.
03:17 Please type the new password again.
03:20 The password is asked twice for security reasons and for confirmation.
03:26 Now our password for the new user is updated.
03:31 We will be asked for other details too.
03:35 But for the time being, I will enter only the “Full Name” as “duck” and leave the rest of the details blank by pressing the Enter key.
03:46 Enter.
03:47 I will confirm this by entering “y”.
03:51 This is to confirm that all the information is correct.
03:55 Let us now check, if the user account has been created.
04:00 To do this, please type the at the command prompt
04:04 “ls space /(slash) home”
04:09 and press Enter.
04:11 To show the list of users in the home folder “ls” command is used.
04:17 And here is our newly created user named “duck”.
04:23 Let me switch back to the slides.
04:26 Now the next command is the “su”
04:30 “su” stands for “Switch User”.
04:34 This command is useful for switching from the current user to another user.
04:39 Let us go to the Terminal now.
04:43 Enter the command
04:45 “su space hyphen space duck” on the “Terminal”and press Enter.
04:53 You will be prompted for a password.
04:56 I shall type the user “duck's” password here please recall that it was “duck” itself.
05:04 Please notice that, the Terminal switches from the previous user to the new user, which is “duck” in our case.
05:14 To logout from this user, type
05:17 “logout” and hit Enter.
05:22 Now the terminal logs out from the current user “duck” and comes back to the previous user account, which is “vinhai” in our case.
05:31 Let us learn about the “usermod” command.
05:35 The “usermod” command
05:37 Enables a super user or root user to modify the settings of other user accounts such as
05:46 Change the password to no password or empty password.
05:50 Show the date on which the user account will be disabled.
05:55 Let us try this command and see.
05:57 Let me switch to the terminal now.
05:59 Let me show you how to set a date of expiry for the user account duck.
06:05 Here at the command prompt type
06:09 sudo space usermod space -(hyphen)e space 2012-(hyphen)12-(hyphen)27 space duck
06:33 and press Enter.
06:37 The user account expiry date is set as mentioned in the command here with the help of the option “-e”.
06:46 Now you have set an expiry date for the user account “duck”.
06:52 Let us now talk about the “uid” and “gid” commands.
06:57 “id – command” is used to check the identities of all the users and groups
07:04 To know about the identity of the user, we use “id space -(hyphen)u”.
07:12 To know about the identity of the group users, it is “id space -(hyphen)g”
07:20 Now lets work on this.
07:22 At the terminal, let us type
07:25 “id” and press Enter.
07:29 Now we can see the User IDs and Group IDs on the system that we are using
07:37 To get only the user id, we use “-(hyphen)u” option.
07:43 Let us type the command, “id space -(hyphen)u”
07:49 and press enter.
07:50 Now we can see only the ids of the users.
07:55 But what if we need to know the names of the users?
08:00 To find that out, we will type
08:02 “id space -(hyphen)n space -(hyphen)u” on the terminal hereand press Enter.
08:13 Now we can see the names of the users instead of their ids.
08:20 Let us now learn the commands for Group IDs.
08:24 Lets type “ id space -(hyphen)g”.
08:29 Here we can see the group ids.
08:32 If we want to view all the current user's group IDs, type
08:38 “id space -(hyphen) (capital)G” and press Enter.
08:46 Please notice that I have typed G in capital letter.
08:50 See the result for yourself.
08:53 Now let us learn how to delete a user account.
08:57 For this we use “userdel” command.
09:00 We can delete an user account permanently with the help of the “userdel” command.
09:07 Lets try this on the terminal.
09:09 Here type “sudo space userdel space -(hyphen)r space duck”.
09:22 I have used the -(hyphen)r option.
09:25 This is to remove the user along with his home directory.
09:30 Let us press Enter and see what happens.
09:34 Now the user “duck” has been deleted.
09:38 Check this by typing
09:41 “ls space /(slash)home” and press the Enter.
09:47 We will find that, the user account “duck” has been deleted.
09:53 Let me go back to the slides now.
09:56 Some of the useful commands in Linux System Administration are “df” and “du”
10:03 The “df” command gives a report on the free space available on the disk.
10:08 And the “du” command gives a report on how much space a file has occupied.
10:13 Please try these two commands and find the output for yourself as an assignment.
10:19 Let us shift to the terminal, I shall show you a fewuseful options used with the “df” command.
10:26 Please type df space -(hyphen)h and press Enter.
10:33 Here it shows the size of the Filesystem, and the space is used.
10:38 It also shows the space mounted on in a human readable format.
10:46 Let us now try some options with the “du” command
10:50 At this point i assume that you have created some text files in your home folder.
10:57 If not please refer to the tutorial on “General Purpose Utilities in Linux”.
11:04 I have already created some text files in my home directory to execute the commands.
11:11 Goto “home folder” on the terminal by typing
11:15 “cd space /(slash) home” and press Enter.
11:20 Then type du space -(hyphen)s space *. (astrix) dot txt and press enter.
11:33 This command will give you a report on the txt files available in the directory along with its file sizes.
11:43 As an assignment, at the command prompt type
11:47 “du space -(hyphen)ch space *.(astrix dot)txt” and see what happens.
11:59 Let me go back to the slides.
12:01 To summarise, we have learnt:
12:03 “adduser” command to create a new user.
12:06 “su” command to switch from one user to another user.
12:09 “usermod” command to change the user account settings.
12:12 “userdel” command to delete the user account.
12:15 id command to know the information about user ids and group ids.
12:20 “df” command to check the file system size and its availability.
12:24 “du” command to check the space occupied by a file.
12:27 This brings us to the end of this tutorial on “Basics of system administration”
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