# fx use

re-use a previous build directory set up by `fx set`

```none
usage: fx use DIR
   or: fx --dir DIR use
   or: fx use

Switches further `fx` commands to using a different build directory.
This only works if `fx --dir DIR set ...` succeeded previously
(and DIR has not been removed since).  The next `fx build` or other
such command will now refer to DIR.  The previous build directory is
left in place, so you can switch back again with `fx use` later.

fx use without arguments will list the available build directories, naming
the current active build directory (if any).
```

[use source code](https://cs.opensource.google/fuchsia/fuchsia/+/main:tools/devshell/use)