UNIX utilities: What is the primary purpose of the cat command when used on a regular text file?

Introduction / Context:
The cat utility (short for “concatenate”) is among the most frequently used UNIX commands. Although it can join multiple files, its most common everyday use is to write the contents of a file to standard output, effectively displaying it on the terminal or piping it to other commands.

Given Data / Assumptions:

• We are discussing cat with a single regular text file argument.
• Output appears on the terminal unless redirected or piped.
• Printing to paper or making filesystem copies is not implied by cat alone.

Concept / Approach:
cat filename reads the file and writes its contents to standard output. This makes it ideal for quick inspections, for feeding content into pipelines (e.g., cat file | grep pattern), and for concatenating several files into a new file via redirection.

Step-by-Step Solution:

Verification / Alternative check:
Compare cat file with less file or more file; less is better for paging, but cat is fastest for streaming small files. For copying, use cp, and for printing to paper, use lp or lpr.

Why Other Options Are Wrong:
capture a file: vague and not a standard term. print a file: printing requires lpr/lp; cat only sends to stdout. copy a file: cp performs copies; cat can be used in redirections but that is not its primary role.

Common Pitfalls:
Using cat for very large files floods the terminal; preferring less/more for paging; unintentionally overwriting files with redirection if careless.

Final Answer:
display a file