The command cd ./../.:

Concept

In a shell pathname, . denotes the current directory and .. denotes its parent directory.

Path components are resolved in sequence; a trailing . keeps the directory reached at that point unchanged.

Application

1. The initial ./ starts from the current working directory.

2. The .. component moves pathname resolution to the parent directory.

3. The final . denotes that same parent directory, so it adds no further movement.

4. The cd command changes the working directory to that resolved parent path.

Cross-check

Starting at /home/user/docs, the path resolves as /home/user/docs → /home/user → /home/user. This is the same destination produced by cd ...

Contrast

• “serves no purpose” does not fit because the working directory changes from the current directory to its parent.

• “is invalid” does not fit because ., .., and / are valid pathname components or separators.

• “None of these” does not fit because equivalence with cd .. is one of the listed descriptions.

Therefore, cd ./../. is equivalent to cd ...