I read this up on this website and it dosentdoesn't make sense.
http://rcsg-gsir.imsb-dsgi.nrc-cnrc.gc.ca/documents/basic/node32.html
When UNIX was first written, /bin
/binand /usr/bin/usr/binphysically resided on two different disks: /bin/binbeing on a smaller faster (more expensive) disk, and /usr/bin/usr/binon a bigger slower disk. Now, /bin/binis a symbolic link to /usr/bin/usr/bin: they are essentially the same directory.
 butBut when you lsls the /bin folder, it has far less content than the /usr/bin folder (atleastat least on my running system).
So can someone please explain the difference?