System Commands Week 4 Graded Assignment Solutions – Unix/Linux Text Processing & Shell Scripting

Master powerful Unix/Linux text processing, regular expressions, and shell array manipulation with this complete solution set for the System Commands Week 4 Graded Assignment. This package provides meticulously explained answers to 12 questions covering grep, egrep, cut, vi editor commands, and Bash array variables.

Key Commands and Concepts Covered

The solutions provide deep and practical insights into advanced command-line usage:

1. Regular Expressions (grep / egrep)

• Word Boundaries (\b): Ensures matching of whole words like raj or Raj, while excluding longer matches like Raja.
• Combined Filtering Logic (-v): Uses patterns like ^#\|^'\|^// to exclude lines starting with comments or quotes.
• Specific Pattern Matching: Applies egrep with regex like [0-9]{16}\s[A-Za-z].* to extract 16-digit credit card numbers followed by usernames.
• grep Options: Explains -n (print line number) and -o (print only the matching part).

2. File Manipulation and Searching

• Finding Files: Uses find . -type f -name '*.cpp' to locate files recursively and filters ls -l output using grep or egrep.
• Column/Delimiter Extraction (cut): Demonstrates cut -c 12- and cut -d ' ' -f1,2 to extract fields from space-separated files.

3. vi / vim Editor Commands

• Substitution Command: Analyzes :%s/UNIX/Linux/gci with flags: g (global), c (confirm), and i (case-insensitive).
• Command Matching: Matches essential vi commands:
  • :q! – Force exit without saving
  • :set number – Display line numbers
  • :x – Save and quit
  • :! – Execute shell command

4. Bash Variables and Arrays

• String Length: Uses ${#var1} to compute the length of a string.
• Associative Arrays: Retrieves keys via ${!caparray[@]} and performs substring extraction like ${caparray[Tokyo]:1:2}.
• Array Manipulation: Demonstrates Bash pattern substitution within array expansion (e.g., ${arr[@]//pattern/replacement}).

What You Get

• 12 Fully Explained Solutions: Each question includes correct command syntax and rationale.
• Regex and Scripting Mastery: Covers advanced grep, cut, and Bash array logic.
• Editor and File Handling: Practical vi usage and file search techniques for real-world tasks.

Build your command-line confidence and secure a top score on your System Commands Week 4 Graded Assignment! 🖥️📂