主要涉及df、du、ls等命令
df 统计文件系统的使用情况。
英文说明：
This manual page documents the GNU version of df. df displays the amount of disk space available on the filesystem containing each file name argument. If no file name is given, the space available on all currently mounted filesystems is shown. Disk space is shown in 1K blocks by default, unless the environment variable POSIXLY_CORRECT
is set, in which case 512-byte blocks are used.
If an argument is the absolute file name of a disk device node containing a mounted filesystem, df shows the space available on that filesystem rather than on the filesystem containing the device node (which is always the root filesystem). This version of df cannot show the space available on unmounted filesystems, because on most kinds of systems doing so requires very nonportable intimate knowledge of filesystem structures.
要点如下：
如果不加参数，显示现在加载的文件系统。默认单位1K-blocks。如果设置了POSIXLY_CORRECT，则以512-byte blocks为单位。该命令针对文件系统，而不是目录，尽管的给的参数可以是目录。
主要参数：
空 显示现在加载的文件系统，不包含0块空间
-a 包含0块空间
－h 易读方式
－k kB为单位
－l 本地
－T 显示文件系统类型
－－sync 返回结果前调用sync命令（有什么用呢？）
实例：
[root@Mother_FLASH ~]# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/md0 28826556 1507948 25854292 6% /usr
/dev/md1 19220436 9153312 9090780 51% /var
/dev/ram1 158667 85032 73635 54% /
/dev/shm 1037388 0 1037388 0% /dev/shm
[root@Mother_FLASH ~]# df -ah
Filesystem Size Used Avail Use% Mounted on
/dev/md0 28G 1.5G 25G 6% /usr
/dev/md1 19G 8.8G 8.7G 51% /var
/dev/ram1 155M 84M 72M 54% /
/dev/proc 0 0 0 - /proc
/dev/sys 0 0 0 - /sys
/dev/devpts 0 0 0 - /dev/pts
/dev/shm 1014M 0 1014M 0% /dev/shm
none 0 0 0 - /proc/sys/fs/binfmt_misc
详细的参考：
-a, --all
include filesystems having 0 blocks
-B, --block-size=SIZE use SIZE-byte blocks
-h, --human-readable
print sizes in human readable format (e.g., 1K 234M 2G)
-H, --si
likewise, but use powers of 1000 not 1024
-i, --inodes
list inode information instead of block usage
-k like --block-size=1K
-l, --local
limit listing to local filesystems
--no-sync
do not invoke sync before getting usage info (default)
-P, --portability
use the POSIX output format
--sync invoke sync before getting usage info
-t, --type=TYPE
limit listing to filesystems of type TYPE
-T, --print-type
print filesystem type
-x, --exclude-type=TYPE
limit listing to filesystems not of type TYPE
-v (ignored)
--help display this help and exit
--version
output version information and exit
SIZE may be (or may be an integer optionally followed by) one of following: kB 1000, K 1024, MB 1000*1000, M
1024*1024, and so on for G, T, P, E, Z, Y.
df 统计每一目录的使用情况。
主要参数：
空 显示现在加载的文件系统，不包含0块空间
-a 统计所有目录和文件，包含隐藏的
－s 只产生一个统计信息
－k kB为单位
－h 易读方式
－L 不计算符号连接
－M 以M为单位。
详细参考
-a, --all
write counts for all files, not just directories
--apparent-size
print apparent sizes, rather than disk usage; although the apparent size is usually smaller, it may be
larger due to holes in (‘sparse’) files, internal fragmentation, indirect blocks, and the like
-B, --block-size=SIZE use SIZE-byte blocks
-b, --bytes
equivalent to ‘--apparent-size --block-size=1’
-c, --total
produce a grand total
-D, --dereference-args
dereference FILEs that are symbolic links
-H like --si, but also evokes a warning; will soon change to be equivalent to --dereference-args (-D)
-h, --human-readable
print sizes in human readable format (e.g., 1K 234M 2G)
--si like -h, but use powers of 1000 not 1024
-k like --block-size=1K
-l, --count-links
count sizes many times if hard linked
-L, --dereference
dereference all symbolic links
-P, --no-dereference
don’t follow any symbolic links (this is the default)
-0, --null
end each output line with 0 byte rather than newline
-S, --separate-dirs
do not include size of subdirectories
-s, --summarize
display only a total for each argument
-x, --one-file-system
skip directories on different filesystems
-X FILE, --exclude-from=FILE
Exclude files that match any pattern in FILE.
--exclude=PATTERN Exclude files that match PATTERN.
--max-depth=N
print the total for a directory (or file, with --all) only if it is N or fewer levels below the command line
argument; --max-depth=0 is the same as --summarize
--help display this help and exit
--version
output version information and exit
ls –lh 可以看出当前目录文件的大小(不含目录), 比如下面的的322M。
[root@LS-SVR-18 ~]# ls -lh
total 322M
-rw-r--r-- 1 root root 312M Aug 1 23:35 10.50.86.18.tar.z
-rw-r--r-- 1 root root 1.3K Aug 1 17:41 anaconda-ks.cfg
drwxr-xr-x 2 root root 4.0K Aug 1 21:44 Desktop
-rw-r--r-- 1 root root 62K Aug 1 17:41 install.log
-rw-r--r-- 1 root root 5.2K Aug 1 17:41 install.log.syslog
-rw-r--r-- 1 root root 8.9M Sep 28 15:29 Install_MSN_Messenger_zhcn.EXE
-rwxr-xr-x 1 root root 9.2K Aug 16 11:20 m64
-rw-r--r-- 1 root root 1.1K Aug 16 11:20 m64.c
-rw-r--r-- 1 root root 1.1K Aug 8 04:33 m64.o
drwxr-xr-x 2 root root 4.0K Oct 9 15:45 MCA
drwxr-xr-x 2 root root 4.0K Oct 9 15:41 MGM
drwxr-xr-x 2 root root 4.0K Oct 9 15:45 MYSQL
-rw------- 1 root root 95 Sep 5 10:34 nohup.out
使用du -sSh 也是同样的结果
[root@LS-SVR-18 ~]# du -sSh
322M
使用du -sh 则包含了子目录的内容
[root@LS-SVR-18 ~]# du -sh
451M .
查看每个文件和目录的大小
[root@LS-SVR-18 ~]# du -sh *
313M 10.50.86.18.tar.z
8.0K anaconda-ks.cfg
8.0K Desktop
72K install.log
12K install.log.syslog
8.9M Install_MSN_Messenger_zhcn.EXE
16K m64
8.0K m64.c
8.0K m64.o
476K MCA
65M MGM
65M MYSQL
8.0K nohup.out
（责任编辑：A6）
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