Linux Shell Scripting

Explore the concept of shells as environments for running commands and scripts. Learn how shell scripting automates repetitive tasks, manipulates files, and links programs across different shell types, including bash.

Explore system variables in the Linux shell, learn how to declare them, assign values with the equals sign, and reference them with the dollar sign in scripts.

Learn how to create and use user variables in shell scripts, assign values like weight, age, and salary, and print them with the dollar sign in the terminal.

Learn how to document shell scripts by adding comments with the hash symbol to explain variables and sections, improving reliability and readability of your code.

Learn to read user input with the read command, store values in variables, handle multiple inputs, mask passwords with -s, and access command line arguments like $1 and $@.

Explore string chopping in Linux shell scripting, using basename to extract file names from absolute paths and remove extensions with options, and dirname to print the directory path.

Learn advanced bash string manipulation with built-in variable expansion, trimming from left or right using double or single hashes and percentile forms for longest or shortest matches.

Learn shell scripting relational operators and if statements using square brackets, with examples of -eq, -ne, -gt, -ge, -lt, -le to categorize ages as child or adult.

Master the and operator in Linux shell scripting to combine conditions, such as verifying an input age is between 18 and 25 and declaring the user a student.

Learn how the logical or operator works in linux shell scripting, executing when any condition is true, with examples using if [ ... ] or [[ ... ]] and -o.

Use echo piping into bc to perform arithmetic operations in Linux shell scripting, including addition, subtraction, multiplication, and division with integers and floating point numbers; note expr limitations.

Explore string operations in Linux shell scripting, using equal to, not equal to, less than, greater than, and null/non-null checks with double square brackets, shown through ABC and XYZ comparisons.

Explore control statements in shell scripting, focusing on the if statement. Implement a simple input check to classify a number as positive or negative.

Explore two for loop syntaxes in Linux shell scripting to iterate over ranges and generate multiplication tables from one to ten and ranges up to a hundred.

Explore the while loop in shell scripting by writing a multiplication table example, showing how to initialize an iterator, test a condition, and increment to avoid infinite loops.

Learn to use the select loop to present a numbered menu of choices, capture the user's selection in a variable, and execute actions accordingly.

Explore the until loop syntax in Linux shell scripting, compare it with the while loop, and see how it repeats while the condition is false and exits when true.

Learn how to use the case statement in shell scripting to route execution to multiple cases using esac, with examples for digits, lower/uppercase letters, and special characters.

Learn how the break statement in Linux shell scripting exits the nearest for, switch, or while loop when a condition is met, controlling loop execution.

Use the continue statement in a for loop over a range to skip the rest of the loop body when the remainder is zero, producing odd numbers.

Learn file test operators in Linux shell scripting to check file existence, type, and permissions, using -e, -f, -s, -r, -w, -x, and -p or -b.

Read file contents using two methods: display the entire file with cat when it exists, and read line by line with a while read loop.

Learn to write data to files in shell scripting by taking user input for a filename, checking existence and permissions, and redirecting output into the file.

Learn to create, delete, rename, and copy file contents using shell scripting, with file existence checks and basic commands like touch.

Learn to count files in the current directory with a for loop, using a file-name variable and tests like -s for non-empty and -f for regular files.

Create and access arrays in shell scripting by defining an array variable, retrieving elements by zero-based index, printing all elements, and computing the array length.

learn to find the biggest and smallest numbers in an array by initializing with the first element and updating through a for loop and if statements.

Define and call functions in shell scripting using two syntaxes, mastering modular blocks and reusable code with examples like hello world and adding numbers.

Learn how to pass arguments to linux shell scripting functions using positional parameters like $1 and $2, and perform operations inside the function.

Learn the difference between local and global variables in shell scripting, including global scope and how to use local declarations to avoid conflicts, and apply read-only variables to lock constants.