The file design.fsf in the current directory is an example of a standard first level FEAT setup file.

Using sed change all instances of the path
/usr/local/fmrib/www/fslcourse/fsl_course_data/melodic/denoise
to
/Users/fsluser/fsl_course_data/UnixIntro
and save the result as a new file.

Generating new design files like this for FEAT allows one design to be used for many different subjects in different directories. You can call FEAT from the command line once you have a valid setup file using the lowercase FEAT command:
feat design.fsf

(cheat)