http://www.unixmen.com/hard-soft-links-user-group-management-rhcsa/

hard-links:
Note: you can't make a hard-link to a directory
Note2: hard-links to a same file should be on the same file system

ls -i
	Show the i-node of (if 2 files have the same one - they are the hard-links)
ls -l
	-//- the 2n-d column shows the number of hard links

soft-links:
Note: you can create a soft-link to a directory

ln -s ...
	create a soft link

ls -F
	show type of files:
	/ - dir
	* - exec file
	@ - symlink
	| - named pipe
	= - unix domain socket
	% - character device
	# - block device

ls -x
	Order files by rows first, instead of columns