On Linux the best available tool for pascal is FreePascal, a great compiler and Lazarus as a RAD IDE (Rapid Application Development / Integrated Development Environment).
Go to this url: http://lazarus-ccr.sourceforge.net/k..._Documentation
It will list many links for pascal tutorials, being that the most basic tutorial is: http://www.taoyue.com/tutorials/pascal/
This is also the Lazarus's Documentation.
The pascal runtime library and the FreePascal runtime library has a reference here: http://www.freepascal.org/docs-html/rtl/index.html
This reference is not nearly as good as Borland Delphi help files, but it will work.
To download "freepascal" and "Lazarus" just google them.