Linux+ Linux+ Bash Scripting and Automation 3

Question 1

Which Bash test expression correctly checks if a file exists AND is readable?

Accepted Answer

[[ -e file && -r file ]]

Answer

[[ -e file && -r file ]] uses the modern double-bracket syntax with && to combine both existence and readability tests.

Question 2

What does the trap command accomplish in a Bash script?

Accepted Answer

Registers a handler to execute when a signal or event occurs

Answer

trap associates a command or function with a signal (like INT or EXIT) so cleanup code runs on termination.

Question 3

In Bash arithmetic, which syntax evaluates an integer expression and returns its value?

Accepted Answer

$(( expr ))

Answer

$(( expr )) is the POSIX-compliant arithmetic expansion syntax for integer math in Bash.

Question 4

Which getopts usage correctly parses a script option '-f' that requires an argument?

Accepted Answer

getopts 'f:' opt

Answer

A colon after the option letter in the optstring tells getopts that the option requires an argument, stored in $OPTARG.

Question 5

What is the output of: echo ${#myvar} when myvar='hello'?

Accepted Answer

5

Answer

${#varname} is the Bash parameter expansion that returns the length of the variable's string value.

Linux Practice Test