Linux & Bash Shell Scripting: Foundation for DevOps & Cloud

Explore basic linux commands for navigation and file management, including present working directory, creating directories with mkdir, listing with ls, changing directories with cd, and creating files with touch.

Use mv to rename or move files and mkdir to create directories. Copy and merge content with cp and cat, create empty files with touch, and review commands with history.

Master grep to search text with regular expressions and print matching lines. Use -i for case-insensitive searches, -c for counts, -v for inverted matches, and -n for line numbers.

Master the Linux pipe to combine commands into a single operation, piping outputs from cat and ls into grep to filter results like .txt files and Docker terms.

Explore how the find command searches files and directories from current location and subdirectories, using options like -type d, -type f, and -empty, and how grep and locate fit in.

Install and use the locate command for fast file searches, learn how its database updates with updatedb, and compare it to find for exhaustive file-system queries.

Learn how to use sudo and su to elevate privileges, switch to the root user, and manage admin tasks in Linux. Understand why permission denied occurs for normal users.

Understand linux file permissions in symbolic mode, covering owner, group, and others with read, write, and execute rights, and learn to view with ls -l and modify them with chmod.

Explore numeric permissions in linux, mapping 0–7 to read, write, and execute, and master chmod examples (777, 755, 644) for owner, group, and others.

Learn how to create, switch between, and manage Linux users and groups with sudo, useradd, and related commands, including home directories and permissions.

Learn to create and manage Linux user groups with groupadd, usermod, and groupdel. Add users to groups, view memberships, rename groups, and delete groups.

Learn how Linux package managers install, update, and remove software across distributions. Use apt on Ubuntu or yum/dnf on Red Hat, verify versions, and manage servers like nginx.

Compare hard and soft links in linux, using inode numbers to show content vs shortcuts, where hard links persist after deletion and soft links break when the original is removed.

Use ip a to view interfaces and inet addresses, and hostname -i for host name. Use ss to inspect tcp and udp connections including ssh activity, listening and established states.

Monitor Linux processes with ps, ps -ef, and grep to identify IDs, view CPU and memory with top, and terminate using kill.

Learn to check Linux system resources using free, free -h, df -h, and du -sh, and monitor cpu, memory, and disk with vmstat every two seconds.

Learn how to find help for linux commands using man, info, and help, with examples like pwd and grep, and distinguish when to use built-in help versus manual pages.

Learn to manage Linux services with systemctl, including starting, stopping, restarting, enabling, disabling, reloading, and checking status, for SSH, Docker, Jenkins, and Apache web servers.

Explore the layered Linux architecture from hardware to kernel, shell, and user applications. The shell mediates commands to the kernel, and the kernel manages memory, files, devices, and networking.

This lecture introduces shell scripting in Linux to automate running multiple commands, covering variables, loops, conditionals, and how to write and execute scripts with bash, sh, and shebang.

Learn decision making in Linux scripts with if-else constructs to run commands based on conditions. Use multiple else if branches, Read user input, and execute scripts in Bash.

Explore shell scripting operators, including numeric, string, and logical (and, or, not) through practical if-else examples, variables, and correct execution in Bash.

Explore loops in shell scripting, including for and while loops, with initialization, condition checks, and updates. Learn how to implement, print outputs, and avoid infinite loops in Bash scripts.

Learn to build reusable bash functions for code automation, with or without the function keyword, and create multi-function scripts that read input, manage files, and start nginx with systemctl.

Explore how Linux environment variables store data, use export for temporary values, and configure per-user or system-wide variables via bashrc and /etc/profile, loaded with source.

Understand how to store multiple values with arrays in shell scripting, and use for loops to access elements and print or deploy automation data.

Discover how the shell case statement replaces long if-else chains by matching input against patterns and executing corresponding commands, with a default option for unknown inputs.

Master cron jobs to schedule Linux commands or shell scripts using cron expressions for minute, hour, day of month, month, and day of week to automate backups and monitoring.