RHEL in Shell Scripting Advanced - RHCSA+.pdf

RHEL in Shell Scripting Advanced - RHCSA+.pdf

• 1.
  Advanced Shell Scripting
• 2.
  User Management Scripts ●Automates user tasks like add, modify, and delete. ● Manages passwords, groups, and permissions efficiently. ● Example : Creates a new user account and confirms successful creation
• 3.
  User Addition ScriptSyntax ● The script begins with "#!/bin/bash", identifying it as a Bash script. ● Syntax: The script follows a sequential structure using essential commands: 'echo', 'read', and 'useradd' ● Script Purpose: Facilitates user account creation through an interactive process ● Command Structure: Uses 'echo' for prompts, 'read' captures user input, 'sudo useradd' creates the account ,and final 'echo' print confirmation message.
• 4.
  ● chmod +xuser.sh - Makes the user.sh script executable by adding execution permissions. ● ./user.sh - Executes the user.sh script from the current directory.
• 5.
  Linux Process Monitoring ●Shows top 5 CPU processes with sorting ● Lists PID, command name, and CPU usage
• 6.
  Process Monitoring ScriptSyntax ● Script Purpose: Lists top CPU-consuming processes ● The script starts with "#!/bin/bash" ● Syntax: Combines 'ps' command with sorting and filtering options ● Command Structure: Uses 'ps -eo' for process listing, '--sort=-%cpu' for sorting, 'head' limits output
• 7.
  ● chmod +xprocess.sh -Makes the process.sh script executable by adding execute permissions. ● ./process.sh -Executes the process.sh script from the current directory to display CPU-intensive processes.
• 8.
  Disk Usage ScriptSyntax ● Script Purpose: Reports disk usage information in readable format ● The script begins with "#!/bin/bash", marking it as a Bash script ● Syntax: Uses 'df' command with '-h' option for human-readable output ● Command Structure: 'echo' provides message, 'df -h' displays formatted disk usage data
• 9.
  ● chmod +xusage.sh -Makes usage.sh executable ● ./usage.sh- Runs the usage.sh script to check disk space
• 10.
  Automated Backup System ●Creates a timestamped backup of home directory using tar ● Stores compressed backups in a dedicated backup folder
• 11.
  Backup Script ● Employsdirectory creation and tar archiving commands with specific options ● The script begins with "#!/bin/bash", designating it as a Bash script ● Script Purpose: Creates automated, dated backups of the home directory ● Command Structure: Defines backup location, creates directory with 'mkdir -p', uses 'tar' for compression, confirms with 'echo'
• 12.
  ● chmod +xbackup.sh -Makes the backup script executable by adding execution permissions. ● ./backup.sh - Runs the backup script to create a compressed archive of the home directory.
• 13.
  Automated Backup Scheduling ●Sets up a cron job to run backup script automatically at 3 AM daily
• 14.
  Cron Job ScriptSyntax ● The script begins with "#!/bin/bash", establishing it as a Bash script ● Syntax: Utilizes crontab commands with schedule parameter "0 3 * * *" ● Script Purpose: Automates backup script scheduling through cron ● Command Structure: Defines cron timing, checks existing jobs with 'crontab -l', adds new job with 'crontab', confirms with 'echo'
• 15.
  ● chmod +xcron.sh - Makes the cron job script executable by adding execution permissions. ● ./cron.sh -Executes the cron job script to schedule automated system backups.