NETW 110 Lab 5 Creating and Assigning Users and Groups Page 1

Transcription

1 NETW 110 Lab 5 Creating and Assigning Users and Groups Page 1 Objective At the conclusion of this lab, the student will be able to add and delete users, create and assign users to groups, and assign users and group privileges using the CLI and XWINDOWS. Journal Assignment From the man pages and online search, write down information, instructions, and options with respect to UNIX and LINUX for the following: pwconv pwunconv useradd userdel groupadd groupmod groupdel passwd gpaswd chage chgrp chown chmod UNIX pipes Find information on the files: /etc/password /etc/shadow /etc/group /etc/gshadow /etc/fstab Procedure 1. Logon as with your general username and assume privileges as su. Make a directory named /home/username/lab05 Make a backup copy of /etc/fstab Since we wish to assign quotas to users, we must modify /etc/fstab. Open the file /etc/fstab in vi There should be a line similar to the following: LABEL=/home /home ext3 defaults 1 2 Change to the insert mode. Move the cursor and add the text,usrquota after defaults with no spaces after the s in defaults, and do not forget the comma before usrquota Save and exit from vi reboot 2. Logon as with your general username and assume privileges as su Copy the file/etc/fstab to the /home/andrewjr/lab05 directory In this course, we want to use shadow passwords. Enable shadow passwords for all users with the command pwconv We will now create user accounts and passwords. The UserIDs in the following table may be different from the ones assigned by the system. From the CLI to create the accounts listed in the following table using the useradd and passwd commands as follows: useradd username passwd username

2 NETW 110 Lab 5 Creating and Assigning Users and Groups Page 2 User Name Name Password UserID Home directory stu01 student 01 stu01pass 501 /home/stu01 stu02 student 02 stu02pass 502 /home/stu02 stu03 student 03 stu03pass 503 /home/stu03 stu04 student 04 stu04pass 504 /home/stu04 When we use this method the UID is automatically assigned. If you created an account for yourself when you booted the system the first time, it was UID 500 by default. After you create the login and password for stu01, verify that the user account was created by entering the command: finger stu01 You should receive a reply that gives you the login name, the Name (if entered), the home directory, the Shell, the date of the last login (never), if the user has mail, and if there is a plan. Since you just created the account, there should be no mail, and no plan. Now let us add four more users, but we will enter a name, a UID and password from the useradd command. The syntax of the command is: useradd c Real Name username -u UID p userpassword To create an account for stu05, the syntax of the command is: useradd c student 05 stu05 -u 505 p stu05pass Now add the other three. User Name Name Password UserID Home directory stu05 student 05 stu05pass 505 /home/stu05 stu06 student 06 stu06pass 506 /home/stu06 stu07 student 07 stu07pass 507 /home/stu07 stu08 student 08 stu08pass 508 /home/stu08 Press CRTL-ALT-F2 to start a new virtual connection. Login as stu08. Verify that you are logged in as stu08 by looking at your prompt. It should be something like [stu08@apple stu08]$ Now let us create a new blank file with the command touch myfile.txt Verify the file was created with the command ls l It should show the file myfile.txt exists and is 0 bytes in size. Now let us modify the file. Enter the command: vi myfile.txt The file opens in the editor. Press i to enter the insert mode. The cursor should be on the first line. Enter the following text: This is my file. Press Esc to enter the command mode. Press :wq to save (write) and quit. Let us verify that the file exists and was modified. Enter the command cat myfile.txt and verify the contents of the file Now logout with the command exit Change back to the root account by pressing CRTL-ALT-F1 Occasionally, it may be necessary to disable a user s account. To prevent the user from logging in, we modify the users password with the l (Lock option) This places an! at the beginning of the users password. Once this is done, any attempt to login will receive a reply as if the user entered an incorrect login or password. Lock the account for stu08 as follows:

3 NETW 110 Lab 5 Creating and Assigning Users and Groups Page 3 passwd l stu08 The system should reply that the password for the user was locked and the passwd command was successfully. Now let us verify that the directory and its contents are still present. Enter the command: ls l /home/stu08 You should see how many files are present, the names of the files and their size. Hidden files are not displayed. To see the hidden files, you need to add the a (all) option ls la /home/stu08 Open a new virtual terminal by pressing CRTL-ALT-F2 Try to login as stu08 When you get tired of trying, Change back to the root account by pressing CRTL-ALT-F1 Unlock the account with the u option passwd u stu08 Open a new virtual terminal with CRTL-ALT-F2 and login as stu08 (successfully this time) Force the user to change his/her password on the next login with the command: chage d 0 stu08 login as stu08 Change the password as required Exit and return to the root account with CTRL-ALT-F1 3. A group is a way to organize users on any Unix-based machine including Linux. Members of a group can share files and directories. For instance, if you have two webmasters of an internet site and both need access to read/write to the files and directories for the website, the two webmasters could be members of the same group and have equal permissions to the files and directories within the group. You must have root access to add a group. After logging in as root, the command groupadd can be used to add groups to your machine. In Red Hat Linux, the groupadd command is located in the /usr/sbin directory. The command to create a group named students with a GID (Group ID) of 600 is: groupadd g 600 f students Now create a group name faculty with a gid of 700 and a group named admin with a gid of 800 To add users to the group in the text mode, you have to edit a file called /etc/group as the root. Enter the command vi /etc/group Press i to enter the insert mode Scroll down until you see a line students:x:600: You add a user to the group by adding the username as a comma delimited list with no spaces after the : or after the last username in the list. Place the cursor at the end of the line students group line and add the user s stu01, stu03, stu05 When you are finished, the line should look like the following: students:x:600:stu01,stu03,stu05 Press ESC Enter :wq Verify that you entries were made to the file with the command cat /etc/group less

4 NETW 110 Lab 5 Creating and Assigning Users and Groups Page 4 You will see one screen of information at a time ( this is cause by adding either less or more at the end of the command). Press the spacebar to scroll in the next screen. (The Enter key scrolls only the next line, and you can use CRTL-C to abort) Continue to scroll until you verify that stu01, stu03, and stu05 were added to the group students. When you get to the end of the file, press q to return to the system prompt. 4. Red Hat has a GUI application called redhat-config-users that only runs from X or from a virtual terminal window in X. If you enter the command from the CLI, you will get a message that the X Server must be running. It allows you to enter the all the information we just did in a graphical environment. While this is convenient, you should know how to use the CLI as this environment only exists in Red Hat. Make sure you are logged in as the root. If not, type exit and login as root. From the CLI, enter the command startx CL on Red Hat Applications Highlight System Setting CL on Users and Groups If necessary, CL on the Users tab. You should see a display similar to the following. We are now going to add four more users as listed in the table below. User Name Name Password UserID Home directory stu09 student 09 stu09pass 509 /home/stu09 stu10 student 10 stu10pass 510 /home/stu10 stu11 student 11 stu11pass 511 /home/stu11 stu12 student 12 stu12pass 512 /home/stu12

5 NETW 110 Lab 5 Creating and Assigning Users and Groups Page 5 It is merely a matter of filling in text boxes in a dialog box so it is much easier that from the CLI. You can manually enter a UID from the bottom right corner of the dialog box, but we will not do that now. From this environment, we can easily see all users and their UID, so there will be no conflicts. CL on Add User and enter the data for stu09 and CL on OK Repeat the previous step for stu10 through stu12. CL on the Groups Tab CL on the students group in the list. CL on Properties CL on the Group Users tab Scroll through the list and place a check in each user from stu01 through stu12 CL on Add Group Name the group techies and assign a group ID manually of 750 Add all students with an odd numbered UID Close the Red Hat User Manager

6 NETW 110 Lab 5 Creating and Assigning Users and Groups Page 6 5. CL on Red Hat - Highlight Accessories - CL on Text Editor CL on File - CL on Open - From the /etc directory, Open the file group Scroll to the end of the file and verify that the group students and techies contain the correct members. Close the file. 6. Switch to the CLI root account Enter the command userdel r stu08 Enter the command ls l /home and verify that the stu08 directory is gone. Enter the command cd /home/stu08, which should fail 7. Press CRL-ALT-F7 to switch to the GUI Open the Users and Groups from the Systems Settings menu. CL on Groups and verify that stu08 was removed from the students group. CL on the Users tab Recreate the user stu08 CL on stu01 and CL on Properties Enter the Full Name student 01 Repeat this step for all users in the list that have no Full Name. Close the Red Hat User Manager and Shutdown X 8. For the following, refer to the quota section of the handout on Creating Users and quotas to perform the following: Change to the single user mode (init 1) Make a backup copy of /etc/fstab and open /etc/fstab in an editor. On the line /home, change defaults to defaults,usrquota Return to runlevel 3 (init 3) Create a quota configuration file with the proper permissions with the commands touch /home/aquota.user chmod 600 /home/aquota.user Create a quota table with the command quotacheck -vagum Set a soft limit for all stu users to a maximum of 5 MB (edquota u username) Set the grace period to 5 days using edquota -t Generate a copy of the quota limits of the /home directory with the command: repquota /home > /home/andrewjr/lab05/quota_report.txt Final Steps 1. With su privileges, copy the following files to the /home/andrewjr/lab05 directory /etc/passwd /etc/shadow /etc/group /etc/gshadow /etc/gshadow /etc/fstab 2. Change the ownership of /home/username/lab05 and all its files from root to your username. Logout as su 3. ftp to the class server and login as your servername. Create a directory named lab05. Upload all the files from /home/username/lab05/ on the local computer to the lab05 directory on the ftp server. Exit from the ftp session. 4. Review documentation and your course text. In your journal, discuss the procedure and commands, and give examples of how to enable other user password options