Mountain Lion Broke MacPorts - Cannot Update

I am trying to update MacPorts but get the following error.

sudo port selfupdate
Password:
--->  Updating MacPorts base sources using rsync
MacPorts base version 2.1.1 installed,
MacPorts base version 2.1.2 downloaded.
--->  Updating the ports tree
--->  MacPorts base is outdated, installing new version 2.1.2
Installing new MacPorts release in /opt/local as root:admin; permissions 0755; Tcl-Package in /Library/Tcl

Error: /opt/local/bin/port: port selfupdate failed: Error installing new MacPorts base: command execution failed

When I follow https://trac.macports.org/wiki/Migration

At stage 3 I get the following error. Is this important or can I continue with it?

Error: Unable to open port: can't read "build.pre_args": can't read "build.cmd": Failed to locate 'gnumake' in path: '/opt/local/bin:/opt/local/sbin:/bin:/sbin:/usr/bin:/usr/sbin' or at its MacPorts configuration time location, did you move it?

Solution 1:

Based on the error in your update, it appears that (as Nathan said) you haven't installed the Xcode commandline tools yet. You should be able to finish the update process after you've done that.