DevOps Lab#1

lab1 from devops diploma on DEPI

1. Create a user account with the following attribute

sudo useradd -m -c "my name is Andrew Adel" -s /bin/bash -p $(openssl passwd -1 "Andrew") AndrewAdel

sudo: Runs the command with superuser privileges. useradd: The command to add a new user.

• -m: Creates a home directory for the new user.
• -c "Fullname/comment": Adds a comment (often used to store the full name of the user).
• -s /bin/bash: Specifies the user's login shell.
• -p $(openssl passwd -1 "password"): Sets the user's password. The openssl passwd -1 command hashes the password.
• username: The username for the new account.
• AndrewAdel: user name

show users

cat /etc/passwd

2. Create a user account with the following attribute

sudo useradd -m -c "Bad User" -s /bin/bash -p $(openssl passwd -1 "baduser") baduser

3. reate a supplementary (Secondary) group called pgroup with group ID of 30000 (Create Groups)

sudo groupadd -g 30000 pgroup

• sudo: Runs the command with superuser privileges.
• groupadd: The command to add a new group.
• -g 30000: Specifies the GID for the new group.
• pgroup: The name of the new group.

show groups and users

cat /etc/groups 

4. Create a supplementary group called badgroup

sudo groupadd -g badgroup

5. Add islam user to the pgroup group as a supplementary group

sudo usermod -aG pgroup islam

show groups of islam

groups islam
id islam

6. Modify the password of islam's account to password

sudo passwd islam

7. Modify islam's account so the password expires after 30 days

set password expire time

sudo chage -M 30 islam

to verify the expire time

sudo chage -l islam

explaination image

8. Lock bad user account so he can't log in

sudo passwd -l baduser

• sudo: Runs the command with superuser privileges.
• passwd: The command used to change user passwords.
• -l: The option to lock the user account ||| -u: The option to unlock the user account
• baduser: The username of the account to be locked.

9. Delete bad user account

sudo userdel -r baduser

• sudo: Runs the command with superuser privileges.
• userdel: The command to delete a user account.
• -r: Removes the user's home directory and mail spool.
• baduser: The username of the account to be deleted.

10. Delete the supplementary group called badgroup

sudo groupdel badgroup

• sudo: Runs the command with superuser privileges.
• groupdel: The command to delete a group.
• badgroup: The name of the group to be deleted.

switch between users

sudo -i -u AndrewAdel

• sudo: Runs the command with superuser privileges.
• -i: runs the shell specified by the target user's default shell as a login shell
• -u: allow run a command as a specified user

11. Create a folder called myteam in your home directory and change its permissions to read only for the owner.

mkdir ~/myteam
chmod 400 ~/myteam

to show:

ls -ld ~/myteam

use the next to show all files and directories with their permission

ls -l

12. Log out and log in by another user || 13. Try to access (by cd command) the folder (myteam)

14. Using the command Line

Change the permissions of oldpasswd file to give owner read and write permissions and for group write and execute and execute only for the others (using chmod in 2 different ways) change your default permissions to be as above.

chmod 631 oldpasswd
chmod u=rw,g=wx,o=x oldpasswd

to show:

ls -l oldpasswd

15. What is the maximum permission a file can have, by default when it is just created? And what is that for directory.

max permission

Direction:

777 (read, write, and execute for owner, group, and others)

Files

666 (read and write for owner, group, and others)

16. Change your default permissions to be no permission to everyone then create a directory and a file to verify

  umask 777
  mkdir dirNewMask
  touch fileNewMask
  umask
  umask 002
  umask
  mkdir dirResetMask
  touch fileResetMask
  ls -ld dirNewMask
  ls -ld dirResetMask
  ls -ld fileNewMask
  ls -ld fileResetMask

17. What are the minimum permission needed for

a. Copy a directory (permission for source directory and permissions for target parent directory)

• source direction: must be

  • readable and excutable at least to be copied and listing its content
  • and its content must be the same (readable and excutable if direction and readable if file)

• target parent direction:

  • must be excutable to be access it and allow changes
  • must be writable to create new file or direction inside it

b. Copy a file (permission for source file and and permission for target parent directory)

• source file:

  • readable

• target parent direction

  • must be excutable to be access it and allow changes
  • must be writable to create new file or direction inside it

c. Delete a file

• source file:

  • no minimum permission requested for the file to be deleted

• parent direction

  • the parent direction must be writable and executable to delete file inside it

d. Change to a directory

need the directiory to be executable

e. List a directory content

need the directory to be executable and readable

f. View a file content (more/cat command)

the file need to be readable

g. Modify a file content

• file:

  • file must be writable

• parent directory

  • must be executable

19. What is the difference between the “x” permission for a file and for a directory?

for file

run file like program or script

for direction

allows you to enter the directory and access its contents.

20. Using vi write your CV in the file mycv. Your CV should include your name, age, school, college, experience

21. Open mycv file using vi command then: Without using arrows state how to:

Show all lines numbers

:set number // show all lines number
/Age //Search for word age
5G //Step to line 5 (assuming that you are in line 1 and file is more than 5 lines).
dd // Delete the line you are on. 

22. List the available shells in your system.

cat /etc/shells

23. List the environment variables in your current shell.

env
// or
printenv

24.List all of the environment variables for the bash shell.

env | grep BASH_

25.What are the commands that list the value of a specific variable?

echo $Variable
\\Example:
echo $SHELL

26. Display your current shell name.

echo $0

27.State the initialization files of: sh, ksh, bash.

what is initialization file

• Initialization files are scripts that are executed automatically when a shell starts up.
• set environment variables
• define functions
• perform other setup tasks

initialization files:

for sh

Login Shell: .profile

• This file is located in the user's home directory ($HOME/.profile).
• It is executed when a login shell starts.
• Example: /home/user/.profile

Non-login Interactive Shell: .shrc

• This file is also located in the user's home directory ($HOME/.shrc).
• It is executed when a non-login interactive shell starts.
• Example: /home/user/.shrc

for ksh

Login Shell: .profile

• Similar to sh, the .profile file in the user's home directory ($HOME/.profile) is executed when a login shell starts.
• Example: /home/user/.profile

Non-login Interactive Shell: .kshrc

• The .kshrc file in the user's home directory ($HOME/.kshrc) is executed when a non-login interactive shell starts.
• Example: /home/user/.kshrc

bash (Bourne Again Shell)

Login Shell:

• .bash_profile, .bash_login, or .profile
• bash looks for these files in the following order: .bash_profile, .bash_login, and .profile.
• It executes the first one it finds in the user's home directory ($HOME).
• Example: /home/user/.bash_profile, /home/user/.bash_login, or /home/user/.profile

Non-login Interactive Shell: .bashrc

• The .bashrc file in the user's home directory ($HOME/.bashrc) is executed when a non-login interactive shell starts.
• Example: /home/user/.bashrc

28. Edit in your profile to display date at login and change your prompt permanently.

add the following code into ~/.profile file

# Display date at login
echo "Today's date: $(date)"

# Customize prompt
export PS1="\[\e[36m\]\u@\h \[\e[33m\]\w\[\e[0m\] $ "

save it and execute the file using source:

source ~/.profile 

29. Execute the following command :

echo \ then press enter

What is the purpose of \ ? * escaping special characters

• indicating that the command continues on the next line.

Notice the prompt ”>” what is that?

The prompt > that appears is called the PS2 prompt, which indicates that the shell is expecting more input to complete the command.

and how can you change it from “>” to “:”. (Search PS1, PS2, ...)

export PS2=": "

30. Create a Bash shell alias named ls for the “ls –l” command

add the alias

test the alias