[ Previous | Next | Contents | Glossary | Home | Search ]
AIX Version 4.3 Commands Reference, Volume 2

df Command


Reports information about space on file systems.


df [ [ -P ] | [ -I | -M | -i | -t | -v ] ] [ -k ] [ -s ] [FileSystem ... | File... ]


The df command displays information about total space and available space on a file system. The FileSystem parameter specifies the name of the device on which the file system resides, the directory on which the file system is mounted, or the relative path name of a file system. The File parameter specifies a file or a directory that is not a mount point. If the File parameter is specified, the df command displays information for the file system on which the file or directory resides. If you do not specify the FileSystem or File parameter, the df command displays information for all currently mounted file systems. File system statistics are displayed in units of 512-byte blocks by default.

The df command gets file system space statistics from the statfs system call. However, specifying the -s flag gets the statistics from the virtual file system (VFS) specific file system helper. If you do not specify arguments with the -s flag and the helper fails to get the statistics, the statfs system call statistics are used. Under certain exceptional conditions, such as when a file system is being modified while the df command is running, the statistics displayed by the df command might not be accurate.

Note: Some remote file systems, such as the Network File System (NFS), do not provide all the information that the df command needs. The df command prints blanks for statistics that the server does not provide.


-i Displays the number of free and used i-nodes for the file system; this output is the default when the specified file system is mounted.
-I Displays information on the total number of blocks, the used space, the free space, the percentage of used space, and the mount point for the file system.
-k Displays statistics in units of 1024-byte blocks.
-M Displays the mount point information for the file system in the second column.
-P Displays information on the file system in POSIX portable format.

When the -P flag is specified, the header line appears similar to:

Filesystem 512-blocks Used Available Capacity Mounted on\n

If the -k flag is specified in addition to the -P flag, the column heading 512-blocks is replaced by the heading 1024-blocks .

File system statistics are displayed on one line in the following order:

FileSystem, TotalSpace, UsedSpace, FreeSpace, UsedPercentage, MountPoint

-s Gets file system statistics from the VFS specific file system helper instead of the statfs system call. Any arguments given when using the -s flag must be a JFS filesystem mount point or device. The filesystem must also be listed in /etc/filesystem.
-t Includes figures for total allocated space in the output.
-v Displays all information for the specified file system.

Exit Status

This command returns the following exit values:

0 Successful completion.
>0 An error occurred.


  1. To display information about all mounted file systems, enter:
    If your system has the /, /usr, /site, and /usr/venus file systems mounted, the output from the df command resembles the following:
    Filesystem 512-blocks Free   %Used   Iused  %Iused  Mounted on
    /dev/hd0    19368     9976    48%     4714    5%     /
    /dev/hd1    24212     4808    80%     5031   19%     /usr
    /dev/hd2     9744     9352     4%     1900    4%     /site
    /dev/hd3     3868     3856     0%      986    0%     /usr/venus 
  2. To display available space on the file system in which your current directory resides, enter:
    df .
    The output from this command resembles the following:
    Device   512-blocks  free   %used   iused   %iused  Mounted on
    /dev/hd4    19368    9976    48%     4714    5%     / 


/etc/filesystems Lists the known file systems and defines their characteristics.
/etc/vfs Contains descriptions of virtual file system types.

Related Information

The fsck command. 

The filesystems file.

The File Systems Overview for System Management in AIX Version 4.3 System Management Guide: Operating System and Devices explains file system types, management, structure, and maintenance.

The Mounting Overview in AIX Version 4.3 System Management Guide: Operating System and Devices explains mounting files and directories, mount points, and automatic mounts.

[ Previous | Next | Contents | Glossary | Home | Search ]