教你詳細了解 Linux文件系統的使用情況

主要涉及df、du、ls等命令

df 統計文件系統的使用情況。

英文說明：

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.

要點如下：

如果不加參數，顯示現在載入的文件系統。默認單位1K-blocks。如果設置了POSIXLY_CORRECT，則以512-byte blocks為單位。該命令針對文件系統，而不是目錄，儘管的給的參數可以是目錄。

主要參數：

空 顯示現在載入的文件系統，不包含0塊空間

-a 包含0塊空間

－h 易讀方式

－k kB為單位

－l 本地

－T 顯示文件系統類型

－－sync 返回結果前調用sync命令（有什麼用呢？）

實例：

[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

詳細的參考：

-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 統計每一目錄的使用情況。

主要參數：

空 顯示現在載入的文件系統，不包含0塊空間

-a 統計所有目錄和文件，包含隱藏的

－s 只產生一個統計信息

－k kB為單位

－h 易讀方式

－L 不計算符號連接

－M 以M為單位。

詳細參考

-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 可以看出當前目錄文件的大小(不含目錄), 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 也是同樣的結果

[root@LS-SVR-18 ~]# du -sSh

322M

使用du -sh 則包含了子目錄的內容

[root@LS-SVR-18 ~]# du -sh

451M .

查看每個文件和目錄的大小

[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

（責任編輯：A6）