I am trying to alter my eclipse configuration, but the eclipse.ini file is not present in my eclipse installation directory.
I am on Mac os x with eclipse 4.2.1 Jun
The file should be found at Eclipse.app/Contents/MacOS/eclipse.ini
For example: /Applications/eclipse/Eclipse.app/Contents/MacOS
Alternatively it might be found instead at Eclipse.app/Contents/Eclipse/eclipse.ini (Both possibilities are noted in different parts of the wiki documentation, and it may be that /Eclipse/ is used for newer versions.)