Bash Shell and Scripting Fundamentals

Examine how user configuration files in the bash shell, such as dot bash_profile, dot bashrc, and dot profile, govern behavior, while local and system-wide files set PATH for child shells.

Understand how bash user configuration files initialize variables in bashrc and have those values inherited by child shells. See how defining sky=blue in bashrc becomes visible when a shell starts.

Edit the profile file in the ATC directory to export http_proxy to the organization proxy, applying it for all users, then log in as a regular user to verify.

Explore the shell environment basics, including standard input and output, redirection, and variables. Learn how to execute scripts, use command substitutions, jobs, aliases, and exit statuses, and understand related terminology.

Explore standard input, standard output, and standard error in Linux programs, understanding how data flows from the terminal into a program and how results and errors are reported.

Learn redirection in Linux by using > to overwrite and >> to append command output to a file, combining system information and IP address outputs for troubleshooting.

Explore redirection of standard error in bash, redirecting errors to error.log, compare single versus double greater-than usage, and append additional standard error as needed.

Explore how bash variables store values in memory, use the assignment operator, and view results with echo, while examining home variable usage, parent and child shells, and unset operations.

Learn how to execute scripts in Unix, understand executable files in directories, and compare path versus current directory and absolute paths through a hands-on lab.

Learn how to manage Bash jobs by running programs in the foreground or background, using sleep, ctrl+z, fg, bg, and ampersand to control processes and return the prompt.

Explore bash shell expansions, including variable and parameter expansion, brace expansion with curly brackets, and base and arithmetic expansions to automate tasks and create directories.

Demonstrates passing values to a script at runtime using positional parameters, showing how the first argument ($1) and second argument ($2) are assigned, with up to nine parameters supported.

Explains the if-then-else conditional construct to control script flow in Linux. It uses return values to decide whether to execute tasks, with syntax including if, then, elif, else.

Learn to use if-then constructs alongside read and echo to interact with users, prompt for input, and display personalized output, while formatting with echo -E and escape sequences.

Explore a scenario-based bash lab that writes a script to detect OS across two environments using string evaluation and cut, ensuring software compatibility and suppressing errors to a null device.

Explore real world scenarios in Bash shell scripting, identify a bad variable, and practice scripting in the RC directory.

Learn how the PATH environment variable enables running scripts from any location by adding a directory to PATH, checking PATH's value, and sourcing a company script that updates PATH.

Learn to use shell scripting in the rc directory on a Linux system, configuring run level 5, creating and executing init scripts, and understanding permissions and symbolic links.

Demonstrate how a for loop iterates over a list using a temporary variable, executing actions like echo and sleep for each value (banana, apple, pear) before completion.

Demonstrate a for loop with a conditional in Bash to back up .sh files by creating the target directory if absent and copying the files into it.

Iterates over three ip addresses, pings each, and extracts packet loss to determine if hosts are alive; reports zero loss for 8.8.8.8 and 8.8.4.4, and 100% loss for 10.10.10.10.

Master the while loop in bash, controlling execution with a condition and counters. Learn how arithmetic capabilities and the command XP influence loop termination.

Explore a bash counter in a while loop by defining sum as 100, incrementing to 101, and using arithmetic expansion to derive a related value minus one, aiming for 9.

Demonstrates a simple Bash while loop that runs while a counter is greater than zero, echoes the current value, sleeps for one second, and decrements by one each iteration.

Implement the bash case statement to match a variable against patterns, execute the corresponding code blocks on matches, and terminate with esac when no patterns match.