Describe the bug
Default Enter-Command fails if Username contains a Backslash "", which is always the case if this is an ActiveDirectory (or LDAP)-Joined System.

Documentation of distrobox enter says it will execute "bash -l", but in reality it will try to use '... -c "\$(getent passwd ${USER}...' - which fails, because you have a Username of e.g. "AD\username".

distrobox enter will fail with "sh: 1: -l: not found", because "getent passwd ..." fails. It will show in the verbose mode:
sh -c "\$(getent passwd Asername | cut -f 7 -d :) -l"

If you specify a Startup command with -- bash -l or -e bash -l, then this works as expected.

To Reproduce
Use a Username like "AD\username".

Expected behavior
Dont fail at the default command or let the default command be set.

Logs
see above

Desktop (please complete the following information):

• docker
• Docker 24.0.5
• Which version of distrobox? 1.6.0.1
• Which host distribution? Ubuntu
• How did you install distrobox? zip

Additional context
Runs in a virtual Desktop environment (Citrix) with Active Directory for Users.