In Racket, how do I get or change my working directory?

Question

What is Racket's equivalent for viewing and changing the working directory of a process like pwd and cd?

Answer 1

Use current-directory.

Passing no arguments returns the current working directory. Passing a path changes the working directory to that path.

Here's an example for the REPL that prints the current directory, then changes to the parent directory:

> (current-directory)
#<path:/home/sage/>
> (current-directory (build-path (current-directory) ".."))
; now in /home

Answer 2

Note that path is a type-object in racket. And because in Racket current-directory does not actually change the environment path but only changes the current-directory path value, if you do this:

> (current-directory "/somepath/thatdoesnt/exist/") ; now in /somepath/thatdoesnt/exist

Racket will not throw an error. You'll only get an error when you try to do something with the path object itself.

such as:

> (directory-list (current-directory)) ; directory-list: could not open directory ; path: /somepath/thatdoesnt/exist/ ; system error: No such file or directory; errno=2 ; [,bt for context]