>> 	echo -n "Creating a fstab..."

   > all of the grammar rules i learned said that it should be 'a' not
   > 'an'...

   The rules I learned say that it depends on how you pronounce "fstab".

The grammar rules I was taught are quite clear that the spelling and
pronunciation of the acronym's expansion, rather than the spelling and
pronunciation of the acronym itself, are what affect grammar.  Hence,
I always say `a NFS server', or `a MMU', or whatever.