NAME

df − Displays statistics on free disk space

SYNOPSIS

The default behavior for the df command is BSD SVR4 compliant.  In this case, the df command uses the following syntax: df [-eiknP] [-t fstype] [file | file_system ...]

To cause the df command to exhibit XPG/4 behavior, set the CMD_ENV environment variable to xpg4.  In this case, the df command uses the following syntax: df [-eiknPt] [-F fstype] [file | file_system ...]

Note

The CMD_ENV environment variable also affects the behavior of the echo command.  The BIN_SH environment variable affects the XPG/4 compliance of the Bourne shell. 

The df command displays statistics on the amount of free disk space on file_system or on the file system that contains the specified file.

FLAGS

-eDisplays information about the mounted file systems, including the mount point, available space, and percentage of space used.  NFS file systems that are served by the automount daemon are usually not displayed. 

-F fstype[XPG4 only] Displays statistics for the specified file system type only.  Available file system types include the following:

sysvSystem V File System

nfsNetwork File System

ufsUNIX File system (Berkeley Fast File System)

cdfsISO 9660 CDROM (Compact Disk Read-Only Memory) file system

-iReports the number of free inodes.  The number of inodes controls the number of files that can exist in a file system. 

-kCauses the numbers to be reported in kilobytes.  By default, all reported BSD compatible numbers are in 512-byte blocks. 

-nDisplays the previously obtained statistics from all mounted file systems.  Use this flag if it is possible that one or more file systems are in a state such that they will not be able to provide statistics without a long delay (for example, if you have a remote file system on a server that has crashed).  If you specify the -n flag, the df command does not request new statistics from the file systems; for some remote file systems, the statistics displayed may be too obsolete to be useful. 

-PProduces output that consists of one line of information for each specified file system, with reported numbers in 512-byte blocks (default). 

-t[XPG4 only] Includes total allocated space figures in the output (default). 

-t [no] fstype
[SVR4 only] Displays statistics for only the specified file system type. If the no prefix is used, all file systems, except the one specified, are displayed. 

cdfsISO 9660 CDROM (Compact Disk Read-Only Memory) File System

nfsNetwork File System

pcfsXenix

ufsUNIX File system (Berkeley Fast File System) (default)

mfsMemory File System

sysvSystem V File System

DESCRIPTION

To obtain XPG/4 compliance, set the environment variable CMD_ENV to xpg4.  If the environment variable is not set or it is set to another value, the environment defaults to BSD.  If neither a file or a file system is specified, statistics for all mounted file systems are displayed. 

When file system disk usage exceeds 100% of the allowed space for users, the df command displays a negative number of free blocks. The allowed space for users is typically 90% of disk capacity, with 10% reserved for use by root only.  However, system administrators may specify either less or more reserved space for use by root. 

System V Compatibility

The root of the directory tree that contains the commands modified for SVID-2 compliance is specified in the file /etc/svid2_path. You can use /etc/svid2_profile as the basis for, or to include in, your .profile.  The file /etc/svid2_profile reads /etc/svid2_path and sets the first entries in the PATH environment variable so that the modified SVID-2 commands are found first. 

The df command, as modified for SVID-2 compliance, accepts one command line option (-t, print space totals) and an optional file system name or device name.  The command displays the mount point, the mounted device, the number of free blocks (in 512-byte quantities), and the number of free inodes.  If the -t option is specified, the command displays, on a separate line following the free block counts, the total number of blocks and inodes for each mounted device. 

Advanced File System

For AdvFS filesets, the df command displays disk space usage information for each fileset.  The kbyte or 512-Blks column shows the maximum amount of space that a fileset can occupy.  Since meta data take away space from the file domain, not all of this space is available for use by the fileset.  Also, if a fileset block quota is set, this column displays the block quota amount.  This is still the maximum amount of space that the fileset can occupy, but it is limited by the quota rather than the size of the file domain. 

RELATED INFORMATION

Commands: du(1), echo(1), mount(8), quot(8), quota(1), sh(1), showfsets(8), vquot(8), vquota(1). 

Functions: fstatfs(2), statfs(2). 

Files: fstab(4).