Other replies already mentioned that the default PATH can be
customized in /etc/profile... However, you can also customize
the default PATH on a per-user basis by creating or adjusting
a .profile script in the user's home directory.
This way you can have . as part of PATH for selected users
and can avoid the associated risks for MANAGER.SYS if desired.
By the way, as of MPE/iX 6.0 you should better customize the
/etc/profile.local script instead of /etc/profile, because the
latter will typically get overwritten by OS updates (and thus
wipe out all your customizations unless you reapply them).
A similar approach will also work on MPE/iX 5.5 if you manually
adjust /etc/profile to source an /etc/profile.local script ;-)
Lars.