After completing an upgrade from Tiger (10.4) to Leopard (10.5), I started poking around to see what's what from a command line point of view. In particular, I wanted to find the differences in Terminal and find out if my MacPorts applications survived.
The most important new feature in Terminal is the addition of tabs. Just as with tabs in a web browser, you can have many Terminals running, but sharing one window. And you can easily switch back and forth among them. To open a new tab, select "Shell / New Tab" from the menu.
Window Groups are new. A window group is a set of Teminal windows that can be saved and opened as a group. If you have a several Terminals open and want to open them all together in the future, go to the Window menu, then select "Save Windows as Group" and give the set a name. Window groups are also opened from the Window menu.
Another new feature is the use of themed shells. In Preferences, under the Settings tab, there are a number of pre-defined themes for new terminals, with names like Grass, Ocean, and Pro. Themes include colors, fonts, backgrounds, etc., and you can define your own. I happen to like a pleasant black font on a white background, but maybe that's because I live in the terminal. For me, odd colors tend to be harder to read, especially over time. You can choose a different theme for each tab or window.
The "Secure Keyboard Entry" menu option has moved from the Shell menu to a more logical place in the Terminal menu. It makes more sense there as a global option. Generally, the Settings are better organized.
One feature I had hoped for was a keep alive for remote connections, but the Leopard Terminal doesn't have it. I tested iTerm 0.9.5.0611 (not upgraded for Leopard) and it continued to run with no problems. If you need the keep alive feature, iTerm is still a good choice.
I did a basic Leopard upgrade from Tiger and installed all the development tools immediately after the upgrade. At the time of this writing, Leopard had been in the wild for about three weeks, but the MacPorts web site had not been updated. No news about how the ports system was affected. This left an uncomfortable informational void in my world view.
A little trial and error showed that all my command line MacPorts programs continued to work perfectly. No harm, no foul.
Even better, I used ports to compile and install an aqua application -- sloth -- and everything worked as expected. When it was done compiling, sloth was ready to run, sitting in the Applications/MacPorts/ folder and ran normally. What a pleasant surprise.
My second attempt to compile an application using ports did not go so well. I tried to install gimp using ports, but the ports command hung immediately at the start of the install. MacPorts doesn't seem to be officially supported on Leopard yet, but some applications are definitely working. YMMV.
A few third party applications did not survive the upgrade:
All were installed from packages compiled for either Panther or Tiger. Overall, the survival rate for third party applications was very high.