Linux以GB显示内存大小

youhaidong@youhaidong-ThinkPad-Edge-E545:~$ free -g
             total       used       free     shared    buffers     cached
Mem:             2          1          1          0          0          0
-/+ buffers/cache:          0          2
Swap:            3          0          3
youhaidong@youhaidong-ThinkPad-Edge-E545:~$ free --giga
             total       used       free     shared    buffers     cached
Mem:             2          1          1          0          0          0
-/+ buffers/cache:          0          2
Swap:            3          0          3