String variables in Bash Scripting - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a string variable in bash scripting?

A string variable in bash scripting is a named storage that holds a sequence of characters, like words or sentences, which you can use and change in your script.

beginner

How do you assign a string value to a variable in bash?

You assign a string to a variable by writing the variable name, an equal sign, and the string without spaces around the equal sign. For example: name="Alice".

beginner

How do you access the value of a string variable in bash?

You access the value by putting a dollar sign before the variable name, like $name. This tells the script to use the stored string.

beginner

What happens if you put spaces around the equal sign when assigning a string variable in bash?

Bash will give an error because spaces are not allowed around the equal sign when assigning variables. It expects var=value without spaces.

beginner

How can you include spaces inside a string variable in bash?

You put the string inside quotes, like greeting="Hello world". Quotes keep the spaces as part of the string.

How do you assign the string 'hello' to a variable named msg in bash?

A msg="hello"

B msg = "hello"

C msg=hello

D msg:hello

In bash, assignment must have no spaces around '=', and strings with spaces or special characters should be in quotes. So msg="hello" is correct.

What does $name mean in a bash script?

A It creates a new variable called name

B It deletes the variable name

C It accesses the value stored in the variable name

D It prints the word '$name'

The dollar sign before a variable name tells bash to use the value stored in that variable.

Which of these is a valid string variable assignment in bash?

A greeting = Hello

B greeting:Hello

C greeting=Hello World

D greeting="Hello World"

You must not have spaces around '=', and strings with spaces must be quoted. So greeting="Hello World" is valid.

What will happen if you run: name =John in bash?

A Variable name is set to 'John'

B Syntax error due to spaces around '='

C Variable name is set to '=John'

D Variable name is unset

Bash does not allow spaces around '=' in variable assignment, so this causes a syntax error.

How do you include spaces inside a string variable in bash?

A Use quotes around the string

B Use backslash before spaces

C Use parentheses around the string

D Spaces are not allowed in string variables

Putting the string inside quotes keeps spaces as part of the string value.

Explain how to create and use a string variable in bash scripting.

Think about how you store and then use a word or sentence in your script.

What common mistake should you avoid when assigning string variables in bash?

Remember how bash reads variable assignments carefully.

Practice

1. What is the correct way to assign the string Hello to a variable named greeting in bash?

easy

A. greeting="Hello"

B. greeting = "Hello"

C. greeting: "Hello"

D. greeting <- "Hello"

Solution

1. Step 1: Understand bash variable assignment syntax

   In bash, variable assignment must have no spaces around the equals sign.

2. Step 2: Check the options for correct syntax

   greeting="Hello" uses no spaces and quotes the string correctly. The other options have invalid syntax.

3. Final Answer:

   greeting="Hello" -> Option A

4. Quick Check:

   No spaces around = and quotes needed [OK]

Hint: No spaces around = and use quotes for strings [OK]

Common Mistakes:

• Adding spaces around = causes syntax errors
• Forgetting quotes around strings with spaces
• Using wrong assignment symbols like : or <-

2. Which of the following correctly prints the value of the variable name in bash?

easy

A. echo name

B. echo $name

C. echo &name

D. echo %name

Solution

1. Step 1: Recall how to access variable values in bash

   Use the dollar sign ($) before the variable name to get its value.

2. Step 2: Evaluate each option

   echo $name uses $name correctly. echo name prints the literal word 'name'. The other options use invalid symbols.

3. Final Answer:

   echo $name -> Option B

4. Quick Check:

   Use $ to access variable value [OK]

Hint: Use $ before variable to print its value [OK]

Common Mistakes:

• Forgetting $ prints variable name, not value
• Using wrong symbols like & or %
• Confusing variable access with assignment

3. What will be the output of this bash script?

name="Alice"
echo "Hello, $name!"

medium

A. Hello, Alice!

B. Hello, $name!

C. Hello, name!

D. Hello, !

Solution

1. Step 1: Understand variable assignment and usage

   The variable name is assigned the string "Alice".

2. Step 2: Analyze the echo command with variable expansion

   The echo command uses double quotes, so $name is replaced by its value "Alice".

3. Final Answer:

   Hello, Alice! -> Option A

4. Quick Check:

   Variables expand inside double quotes [OK]

Hint: Variables expand inside double quotes, not single quotes [OK]

Common Mistakes:

• Expecting variable expansion inside single quotes
• Printing variable name literally without $
• Forgetting to assign variable before use

4. Identify the error in this bash script:

message = "Hi there"
echo $message

medium

A. Variable name is invalid

B. Quotes should be single quotes

C. Missing $ before variable in echo

D. Spaces around = cause syntax error

Solution

1. Step 1: Check variable assignment syntax

   In bash, no spaces are allowed around the equals sign when assigning variables.

2. Step 2: Analyze the given script

   The line message = "Hi there" has spaces around =, causing a syntax error.

3. Final Answer:

   Spaces around = cause syntax error -> Option D

4. Quick Check:

   No spaces around = in assignments [OK]

Hint: No spaces around = in variable assignment [OK]

Common Mistakes:

• Adding spaces around =
• Using wrong quotes type causes no error here
• Forgetting $ in echo prints variable name literally

5. You want to store a user's full name with spaces in a variable fullname and then print it. Which script correctly does this?

hard

A. fullname=John Doe
echo $fullname

B. fullname='John Doe'
echo fullname

C. fullname="John Doe"
echo $fullname

D. fullname=John_Doe
echo $fullname

Solution

1. Step 1: Assign string with spaces to variable

   Strings with spaces must be quoted to be assigned correctly in bash.

2. Step 2: Print the variable value

   Use echo $fullname to print the stored string value.

3. Final Answer:

   fullname="John Doe" echo $fullname -> Option C

4. Quick Check:

   Quote strings with spaces and use $ to print [OK]

Hint: Quote strings with spaces; use $ to print variable [OK]

Common Mistakes:

• Not quoting strings with spaces causes errors
• Printing variable name without $ prints literal text
• Using underscores instead of spaces changes the string