Linux Shell Scripting 4

Question 1

Which bash arithmetic syntax correctly increments a variable `count`?

Accepted Answer

((count++))

Answer

`(( ))` is bash's arithmetic evaluation context, where C-style expressions like `count++` are valid.

Question 2

What does the `-f` flag test for in `[ -f filename ]`?

Accepted Answer

File exists and is a regular file

Answer

`-f` checks that the path exists and is a regular file (not a directory or device).

Question 3

How does `while IFS= read -r line; do ...; done < file.txt` work?

Accepted Answer

Reads file.txt line by line, preserving whitespace and backslashes

Answer

Setting `IFS=` prevents whitespace stripping and `-r` prevents backslash processing, giving raw lines.

Question 4

What is the result of `echo "${var:-default}"` when `var` is unset?

Accepted Answer

Prints 'default'

Answer

`${var:-default}` expands to `default` if `var` is unset or empty, without modifying `var`.

Question 5

Which command within a script will print the script's own filename?

Accepted Answer

echo $0

Answer

`$0` holds the name or path of the running script (or the shell name if running interactively).

Linux Practice Test