Shell Script Programming

Explanation

Here is an explanation of the Bash script:

1. Purpose

This program generates a right-angled triangle pattern of stars (*). It uses a loop to print an increasing number of stars on each line, building up from 1 star to 5 stars.

2. Key Concepts

• C-Style for Loop: Used to repeat an action a specific number of times ((( i=1; i<=5; i++ ))).
• String Concatenation: Appending a new character to an existing string variable in each iteration (pattern="$pattern*").
• Variable Initialization: Starting with an empty string before entering the loop.

3. Code Walkthrough

• pattern=""
  Initializes an empty string variable named pattern to hold the stars.
• for (( i=1; i<=5; i++ )); do
  Starts a loop where a counter i begins at 1 and increases by 1 until it reaches 5 (running 5 times total).
• pattern="$pattern*"
  Appends one asterisk (*) to the existing pattern variable during each loop cycle.
• echo "$pattern"
  Prints the updated pattern string to the terminal on a new line.
• done
  Marks the end of the for loop block.

4. Output

*
**
***
****
*****