010-160 Basic Scripting Concepts 4

Question 1

What does the `-z` test operator check in `[ -z "$var" ]`?

Accepted Answer

Whether $var is an empty string

Answer

`-z` returns true when the string has a length of zero.

Question 2

Which command substitution syntax is POSIX-compatible and preferred in modern scripts?

Accepted Answer

$(command)

Answer

`$(command)` is the modern, nestable form of command substitution recommended by POSIX.

Question 3

What value does `$#` represent in a shell script?

Accepted Answer

The number of positional parameters passed

Answer

`$#` expands to the count of positional parameters supplied when the script was invoked.

Question 4

How do you make a script file executable so it can be run as `./myscript.sh`?

Accepted Answer

chmod +x myscript.sh

Answer

`chmod +x` adds the execute permission bit, allowing the file to be run directly.

Question 5

In bash, what is the correct way to compare two integer variables `a` and `b` for equality inside `[ ]`?

Accepted Answer

[ $a -eq $b ]

Answer

`-eq` is the arithmetic equality operator used inside `[ ]` for numeric comparisons.

(010-160) LPI Linux Essentials Practice Test