Is there a way to self-update without messing with a particular installation ?

[Jeremy Lavergne]

> I have had this problems twice now where I performed a port selfupdate and it ended up changing my version of Perl to 5.12.4.   This wouldn't have been that bad, except that it appeared that the previous version , 5.10.1 was deleted. This was a problem because the number of Perl modules that I have to install to get our product working is quite large and takes a while to install (and even hack to get some working ), so I would prefer not to go this route again.
> 
> I am asking this question now because I currently am getting messages informing me that I must "selfupdate" my ports again, but I am really hesitant to do this if my Perl distro might get removed again.
> 
> 
> Should the "port selfupdate" actually remove existing packages , like a Perl , or did I just do something strange with my invocation of the command ? Is there a way to guard against this ? 
> 
> Thanks for any information that could shed light on this matter,

Selfupdate simply updates MacPorts itself and the portfiles that direct MacPorts on how to build and install various packages.

Selfupdate doesn't actually remove software from your computer--something else would have to be run after a selfupdate, such as running `sudo port upgrade outdated` or installing a package that triggers upgrades of the already-installed packages.