Reading into multiple variables in Bash Scripting - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this Bash script reading into multiple variables?

Consider the following Bash script that reads a line of input into three variables. What will be the output if the input is apple banana cherry?

Bash Scripting

read a b c <<< "apple banana cherry"
echo "$a"
echo "$b"
echo "$c"

A

apple banana cherry

B

apple banana
cherry

C

apple
banana cherry

D

apple
banana
cherry

💡 Hint

Remember that the read command splits input by spaces and assigns each word to a variable in order.

The read command splits the input string by spaces and assigns each word to the variables a, b, and c respectively. So a='apple', b='banana', c='cherry'.

💻 Command Output

intermediate

What happens when input has more words than variables in Bash read?

Given this script, what will be the output if the input is red green blue yellow?

Bash Scripting

read x y z <<< "red green blue yellow"
echo "$x"
echo "$y"
echo "$z"

A

red green
blue
yellow

B

red
green
blue

C

red
green
blue yellow

D

red green blue
yellow

💡 Hint

The last variable gets all remaining words after the previous variables are assigned.

When there are more words than variables, the last variable gets all remaining words joined by spaces.

🔧 Debug

advanced

Why does this Bash script fail to assign variables correctly?

This script is intended to read three words into variables a, b, and c, but it does not work as expected. What is the error?

Bash Scripting

read a, b, c <<< "one two three"
echo "$a $b $c"

A SyntaxError: commas are not allowed in variable list for read

B a=one, b=two, c=three

C one two three

D one two three with commas

💡 Hint

Check the syntax of the read command variable list.

The read command does not accept commas between variable names. Commas cause a syntax error.

💻 Command Output

advanced

What is the output when reading input with IFS set to comma?

Given this script, what will be the output if the input is dog,cat,bird?

Bash Scripting

IFS=',' read animal1 animal2 animal3 <<< "dog,cat,bird"
echo "$animal1"
echo "$animal2"
echo "$animal3"

A

dog
cat,bird

B

dog
cat
bird

C dog cat bird

D

dog,cat,bird

💡 Hint

IFS defines the delimiter for splitting input in read.

Setting IFS to comma makes read split input at commas, assigning each word to variables.

🚀 Application

expert

How many variables are assigned when reading input with fewer variables than words?

Consider this script reading input with 5 words but only 3 variables. How many variables will be assigned and what is the value of the last variable?

Bash Scripting

read v1 v2 v3 <<< "one two three four five"
echo "$v1"
echo "$v2"
echo "$v3"

A 3 variables assigned; v3='three four five'

B 5 variables assigned; v3='five'

C 3 variables assigned; v3='three'

D 2 variables assigned; v3 is empty

💡 Hint

The last variable gets all remaining words after previous variables are assigned.

When fewer variables than words, the last variable gets all remaining words as a single string.