Linux下查看磁盘空间使用
1>df是以磁盘分区为单位来查看磁盘的使用情况：
[root@order properties]# df -lh
Filesystem                    Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup-lv_root  50G   14G   34G  30% /
tmpfs                         3.8G     0  3.8G   0% /dev/shm
/dev/sda1                     485M   32M  429M   7% /boot
/dev/mapper/VolGroup-lv_home  42G  4.5G   35G  12% /home
参数说明:
  -h  --human-readable  print sizes in human readable format (e.g., 1K 234M 2G)
  -l  limit listing to local file systems
   --help     display this help and exit

2>du是用来统计某个目录下面的文件大小:
[root@order properties]# du -h -s /* | sort
du: cannot access `/proc/20989/task/20989/fd/4': No such file or directory
du: cannot access `/proc/20989/task/20989/fdinfo/4': No such file or directory
du: cannot access `/proc/20989/fd/4': No such file or directory
du: cannot access `/proc/20989/fdinfo/4': No such file or directory
0       /proc
0       /selinux
0       /sys
11G     /export
127M    /lib
1.4G    /usr
160K    /dev
16K     /lost+found
183M    /root
20M     /lib64
21M     /boot
22M     /etc
33M     /test
4.0K    /bin.zip
4.0K    /media
4.0K    /mnt
4.0K    /opt
4.0K    /srv
4.4G    /home
460K    /tmp
468K    /order_logs
511M    /var
5.7M    /bin
9.9M    /sbin

参数说明:
-s   --summarize       display only a total for each argument
-h   --human-readable  print sizes in human readable format
-b   --bytes           equivalent to `--apparent-size --block-size=1 -k                    like --block-size=1K
-m                    like --block-size=1M