I am using GIMP on my Ubuntu, and need to open a file some one else made with Photoshop. What file format preserves the layers, colors and preferably the text/fonts when exporting from Photoshop and importing to GIMP?
GIMP can open fairly basic PSDs (those with layers and text layers), but not all the features of Photoshop are supported, so there may be loss of things like Layer Effects/Styles.
GIMPs native format is XCF. You should save in XCF for full compatibility with GIMP, if you want to preserve layers, etc.
Photoshop doesn't support XCF at all, unfortunately.