notes update

src/rhcsa.md

@@ -1028,4 +1028,182 @@ systemctl --user enable container-mynginx.service # enable the mynginx service
 systemctl --user status container-mynginx.service # check the status of the mynginx service
 
 ### after rebooting the system, the service will start automatically
-```
+```
+
+## Create Archives and Compress Files
+
+### Using gzip and bzip2
+```bash
+### gzip
+gzip file.txt # Compress the file.txt file
+gunzip file.txt.gz # Decompress the file.txt.gz file
+zcat file.txt.gz # Display the contents of the file.txt.gz file
+
+### bzip2
+bzip2 file.txt # Compress the file.txt file
+bunzip2 file.txt.bz2 # Decompress the file.txt.bz2 file
+bzcat file.txt.bz2 # Display the contents of the file.txt.bz2 file
+```
+
+### Using xz and zip
+```bash
+### xz
+xz file.txt # Compress the file.txt file
+unxz file.txt.xz # Decompress the file.txt.xz file
+xzcat file.txt.xz # Display the contents of the file.txt.xz file
+
+### zip
+zip file.zip file.txt # Compress the file.txt file
+zip file.zip file1.txt file2.txt # Compress multiple files
+unzip file.zip # Decompress the file.zip file
+zipinfo file.zip # Display the contents of the file.zip file
+```
+
+### Tar and Star
+```bash
+### tar
+tar -cvf archive.tar file.txt # Create an archive of the file.txt file
+tar -xvf archive.tar # Decompress the archive.tar file
+tar -tvf archive.tar # Display the contents of the archive.tar file
+
+### tar with compression
+tar -czvf archive.tar.gz file.txt # Create an archive of the file.txt file with compression
+tar -cjvf archive.tar.bz2 file.txt # Create an archive of the file.txt file with compression
+tar -cJvf archive.tar.xz file.txt # Create an archive of the file.txt file with compression
+
+### star basic commands
+star -cf archive.tar file.txt # Create an archive of the file.txt file
+star -xf archive.tar # Decompress the archive.tar file
+star -tvf archive.tar # Display the contents of the archive.tar file
+```
+
+### Finding Files to Archive
+```bash
+### find
+sudo find / -type f -name "*.txt" # Find all files with a .txt extension
+
+### cpio
+sudo find / -type f -name "*.txt" | cpio -ocvB > archive.cpio # Create an archive of the files
+
+### cpio extract
+cpio -idv < archive.cpio # Extract the archive.cpio file
+
+### cpio with compression
+sudo find / -type f -name "*.txt" | cpio -ocvB | gzip > archive.cpio.gz # Create an archive of the files with compression
+
+
+### cpio with compression extract
+gunzip -c archive.cpio.gz | cpio -idv # Extract the archive.cpio.gz file
+```
+
+## Manage Users, Groups and Shells
+
+### Creating New Users
+```bash
+sudo useradd user1 # Create a new user
+sudo useradd -m user1 # Create a new user and home directory
+sudo useradd -s /bin/bash user1 # Create a new user and set the shell to bash
+sudo useradd -c "User One" user1 # Create a new user and set the comment to User One
+```
+
+### Controlling Default Values
+```bash
+### default useradd configuration file
+sudo vim /etc/default/useradd
+
+### skeleton directory
+cd /etc/skel
+
+### create a file in the skeleton directory
+echo "This is a test file" > test.txt
+
+### when a new user is created, the files in the skeleton directory are copied to the user's home directory
+sudo useradd user1
+
+### check the home directory
+ls -a /home/user1
+
+### login.defs configuration file
+sudo vim /etc/login.defs
+
+### change the default shell to bash
+DEFAULT_SHELL=/bin/bash
+
+### change the default group to users
+DEFAULT_GROUP=users
+```
+
+### Deleting Users
+```bash
+sudo userdel user1 # Delete the user
+sudo userdel -r user1 # Delete the user and home directory
+```
+
+### User Modification
+```bash
+sudo usermod -c "User One" user1 # Change the comment to User One
+sudo usermod -s /sbin/nologin user1 # Change the shell to nologin
+sudo usermod -aG users user1 # Add the user to the users group
+
+sudo usermod -L user1 # Lock the user
+sudo usermod -U user1 # Unlock the user
+
+sudo usermod -d /home/user2 user1 # Change the home directory to /home/user2
+sudo usermod -m -d /home/user2 user1 # Change the home directory to /home/user2 and move the user's files to the new directory
+```
+
+### Understanding Groups
+```bash
+sudo groupadd admins # Create a new group
+sudo groupadd -g 1000 admins # Create a new group with a specific group ID
+
+sudo groupdel admins # Delete the group
+
+sudo groupmod -n admins admin # Change the group name to admin
+sudo groupmod -g 1000 admins # Change the group ID to 1000
+
+sudo groupmod -aG admins user1 # Add the user to the admins group
+
+### lid
+lid -g admins # Display the members of the admins group
+```
+
+### Assigning Privileges to Groups
+```bash
+### visudo
+sudo visudo # Edit the sudoers file
+
+### add the following line to the sudoers file
+%admins ALL=(ALL) ALL
+
+### dnf update for tier-4 admin group 
+%tier4admin ALL=(ALL) NOPASSWD: /usr/bin/dnf update
+```
+
+### The Passwd and Shadow Files
+```bash
+### passwd file
+sudo vim /etc/passwd
+
+### shadow file
+sudo vim /etc/shadow
+
+### chage
+chage -l user1 # Display the user's password expiration information
+
+chage -m 0 user1 # Set the minimum password age to 0
+chage -M 90 user1 # Set the maximum password age to 90 days
+chage -E -1 user1 # Set the password to never expire
+chage -E 2025-03-07 user1 # Set the password to expire on a specific date
+```
+
+## Process Text & Create Links
+
+### Redirection Basics
+```bash
+### redirect the output of the ls command to a file
+ls -l > output.txt
+
+### redirect the output of the ls command to a file and append to the file
+ls -l >> output.txt
+```