All you have to do, to extend your trial period, is change number in TrialKey element in application.xml. This file is located in /Library/Application Support/Adobe/Adobe Photoshop/AMT. You can navigate there with this command:
cd /Library/Application\ Support/Adobe/Adobe\ Photoshop\ */AMT
Then you have to open the file and edit it. You can use just TextEdit app.
open -a TextEdit application.xml
Now find the TrialSerialNumber Data key:
<Data key="TrialSerialNumber">911997074887979240115317</Data>
And increment this number by one:
<Data key="TrialSerialNumber">911997074887979240115318</Data>
And that’s it. Now when you relaunch Photoshop you will be prompted to login and you should see fresh 7 days of trial.
After you do this for CS6 Photoshop it asks you to sign in which it can't do anymore since the servers closed down. Is there any way to extend the trial of CS6?