Tilde expansion (~) in Bash Scripting - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the tilde (~) symbol represent in bash scripting?

The tilde (~) represents the current user's home directory path. For example, ~ expands to /home/username.

beginner

How does bash handle the tilde (~) when used at the start of a path?

Bash replaces the tilde (~) at the start of a path with the full path of the user's home directory before running the command.

intermediate

What happens if you use ~username in bash?

Using ~username expands to the home directory of the specified user, not the current user. For example, ~john expands to /home/john.

intermediate

Does tilde expansion happen if ~ is used in the middle of a path, like /tmp/~/file?

No, tilde expansion only happens if ~ is at the start of the path or immediately after a colon (:). In /tmp/~/file, ~ is treated as a normal folder name.

intermediate

Can tilde expansion be used inside quotes in bash?

Tilde expansion does NOT happen inside single quotes ('~'), and it does NOT happen inside double quotes ("~").

What does the command cd ~ do in bash?

A Changes directory to the current user's home directory

B Changes directory to the root directory

C Changes directory to a folder named ~ in the current directory

D Throws an error

The tilde (~) expands to the current user's home directory, so cd ~ moves you there.

What will echo ~john output if user 'john' exists?

A The current user's home directory

B The string '~john' literally

C The home directory path of user 'john'

D An error message

Using ~username expands to that user's home directory if the user exists.

Which of these paths will NOT trigger tilde expansion?

A /tmp/~/file

B ~/documents

C :~/.bashrc

D ~

Tilde expansion only happens at the start of a path or after a colon (:). In /tmp/~/file, ~ is in the middle and treated literally.

Does tilde expansion occur inside single quotes in bash?

A Yes, always

B No, never

C Only if the quotes are empty

D Only if the tilde is at the end

Tilde expansion does not happen inside single quotes because single quotes prevent all expansions.

What does the command ls ~ do?

A Lists files in the current directory

B Lists files in a folder named ~

C Lists files in the root directory

D Lists files in the user's home directory

~ expands to the user's home directory, so ls ~ lists files there.

Explain what tilde expansion (~) is and how it helps when working with file paths in bash.

Think about how ~ saves you from typing full home directory paths.

Describe when tilde expansion does NOT happen in bash and why that matters.

Consider how quoting and position affect tilde behavior.