Detailed explanation of linux df command

The function of the df command in Linux is to check the disk space usage of the file system of the Linux server. You can use this command to obtain information such as how much space is occupied on the hard disk and how much space is currently left.

command Format: (Recommended learning: linux tutorial )

df [选项] [文件]

## command function:

Display the available space of the specified disk file. If no filename is specified, the available space for all currently mounted file systems will be displayed. By default, disk space will be displayed in 1KB units, unless the environment variable POSIXLY_CORRECT is specified, in which case it will be displayed in 512-byte units

Command parameters:

Required parameters:

-a 全部文件系统列表
-h 方便阅读方式显示
-H 等于“-h”，但是计算式，1K=1000，而不是1K=1024
-i 显示inode信息
-k 区块为1024字节
-l 只显示本地文件系统
-m 区块为1048576字节
--no-sync 忽略 sync 命令
-P 输出格式为POSIX
--sync 在取得磁盘信息前，先执行sync命令
-T 文件系统类型

Selected parameters:

--block-size=<区块大小> 指定区块大小
-t<文件系统类型> 只显示选定文件系统的磁盘信息
-x<文件系统类型> 不显示选定文件系统的磁盘信息
--help 显示帮助信息
--version 显示版本信息

Usage examples:

Display disk usage

Command:

df

Output:

[root@CT1190 log]# df
文件系统               1K-块        已用     可用 已用% 挂载点
/dev/sda7             19840892    890896  17925856   5% /
/dev/sda9            203727156 112797500  80413912  59% /opt
/dev/sda8              4956284    570080   4130372  13% /var
/dev/sda6             19840892   1977568  16839184  11% /usr
/dev/sda3               988116     23880    913232   3% /boot
tmpfs                 16473212         0  16473212   0% /dev/shm

Description:

The first column of the output list of the df command in Linux is the path name of the device file corresponding to the file system (usually a partition on the hard disk); the second column gives the data blocks contained in the partition. (1024 bytes); columns 3 and 4 indicate the number of used and available data blocks respectively.

Users may find it strange that the sum of the block numbers in columns 3 and 4 is not equal to the number of blocks in column 2. This is because by default each partition leaves a small amount of space for system administrators to use.

Even if the normal user space is full, the administrator can still log in and have the workspace needed to solve the problem.

The Use% column in the list indicates the percentage of space used by ordinary users. Even if this number reaches 100%, the partition still leaves space used by the system administrator. Finally, the Mounted on column represents the mount point of the file system.

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