While entering the environment with anch command, the specialized scripts are performed:

any/bin/dobefore

is launched out of environment before the shifting inside.

any/bin/enter

is launched inside isolated environment in a separate process before the target command (like do).

any/bin/doafter

is launched out of environment after the target command has finished.

The scripts above set up the host automatically so that filesystem would be suitable for the build: initialise virtual filesystems (proc in Linux), create device files in ./dev/.

With the any-choff(1) command one may remove the traces of host settings. The host will return to the plain directory: no virtual filesystems, device files in ./dev and other such stuff.

        any choff

Before removing of working directory it is required to perform any choff, if the isolated build has been launched there before.

The variables are used with the settings for isolation:

PROGCHROOT

keeps the command to enter the host environment.
Defaults to sudo chroot.

PROGSU

keeps the command to change the user inside host. It is used to run process inside environment under the same user, as outside.
Defaults to /usr/bin/sudo.

See more details about isolated launches in any-do(1).