Determine if relative or absolute path in shell program

Question

As stated in the title, I need to determine when a program is ran if the path is relative or absolute:

./program #relative
dir/dir2/program #relative
~User/d         


        

Answer 1

A general solution for any $path, rather than just $0

POSIX One Liner

[ "$path" != "${path#/}" ] && echo "absolute" || echo "relative"