size of files

hello Experts,can any one tell me that i have a folder data in linux.
and there are three files A,B,C in the directory.
cany any one tell me the command that which can tell me how much space is occupied by each file and its free space also
for example

FILES USED SPACE FREE SPACE
A 5MB 1MB
B 10MB 5MB
C 20MB 6MB

REGARDS,
shary

ls -l gives the size of a file. df gives the free space on the filesystems where the file lives. du is another command. quota -v (if quotas are enabled) tells you how much more filespace and how many more files you can create.

Other than holes, files don't have "free" space - the application that allocated the file will keep track of space inside the file it has not used. databases do this kind of thing, for example.