What's the difference between alias and link? I see that the size of alias is 167.7kB, whereas symbolic link is just 4kB. 


What's the difference between the two, or what's the purpose of them?
Which one is preferable? For the case that the link/alias is used only in one machine or networked.


ADDED

http://prosseek.blogspot.com/2012/12/symbolic-link-and-alias-in-mac.html
An alias contains two pieces of information: a unique identifier of the file it links to, and the path and file name of the file it links to.

If you rename or move a file, and then create a new file with the path and file name that the file originally had, then any alias that linked to the original file now links to the new file.

However, if you rename or move a file without replacing it, and then invoke an alias, the alias is updated to point to the new path and file name, making use of the unique identifier to do so.

A symbolic link, on the other hand, does not contain a unique identifier to a file, and would appear as broken if the file is renamed or moved and not replaced with a file of the same path and file name.

Your choice should depend on which scenario suits you best.