ORDERS(7) BSD Miscellaneous Information Manual ORDERS(7)NAME
orders -- orders of magnitude
DESCRIPTION
The following table lists common multiples of bytes.
Name Prefix Power of 2 Power of 10
Kilobyte kB 2^10 10^3
Megabyte MB 2^20 10^6
Gigabyte GB 2^30 10^9
Terabyte TB 2^40 10^12
Petabyte PB 2^50 10^15
Exabyte EB 2^60 10^18
Zettabyte ZB 2^70 10^21
Yottabyte YB 2^80 10^24
The following table lists common bit rates as a power of ten.
Name Prefix Bit per second Byte per second
Bit per second bit/s 1 0.125
Byte per second B/s 8 1
Kilobit per second kbit/s 10^3 125
Kilobyte per second kB/s 8 * 10^3 1000
Megabit per second Mbit/s 10^6 125000
Megabyte per second MB/s 8 * 10^6 1000000
Gigabit per second Gbit/s 10^9 125000000
Gigabyte per second GB/s 8 * 10^9 1000000000
Terabit per second Tbit/s 10^12 125000000000
Terabyte per second TB/s 8 * 10^12 1000000000000
The following table lists common orders of magnitude as a power of ten.
Name Order Prefix Symbol Decimal
Septillionth 10^-24 yocto y 0.000000000000000000000001
Sextillionth 10^-21 zepto z 0.000000000000000000001
Quintillionth 10^-18 atto a 0.000000000000000001
Quadrillionth 10^-15 femto f 0.000000000000001
Trillionth 10^-12 pico p 0.000000000001
Billionth 10^-9 nano n 0.000000001
Millionth 10^-6 micro mu 0.000001
Thousandth 10^-3 milli m 0.001
Hundredth 10^-2 centi c 0.01
Tenth 10^-1 deci d 0.1
One 10^0 - - 1
Ten 10^1 deca da 10
Hundred 10^2 hecto h 100
Thousand 10^3 kilo k 1000
Million 10^6 mega M 1000000
Billion 10^9 giga G 1000000000
Trillion 10^12 tera T 1000000000000
Quadrillion 10^15 peta P 1000000000000000
Quintillion 10^18 exa E 1000000000000000000
Sextillion 10^21 zetta Z 1000000000000000000000
Septillion 10^24 yotta Y 1000000000000000000000000
SEE ALSO units(1), strsuftoll(3), number(6)STANDARDS
There have been various attempts to standardize the set of binary prefixes. Organizations such as International Electrotechnical Commission
(IEC) have proposed new prefixes such as ``kibi'', ``mebi'', ``gibi'', and ``yobi'', but the adoption has been slow at best.
BSD August 6, 2011 BSD
Check Out this Related Man Page
DF(1) BSD General Commands Manual DF(1)NAME
df -- display free disk space
SYNOPSIS
df [-b | -h | -H | -k | -m | -P] [-ailn] [-t type] [file | filesystem ...]
DESCRIPTION
The df utility displays statistics about the amount of free disk space on the specified filesystem or on the filesystem of which file is a
part. Values are displayed in 512-byte per block counts. If neither a file or a filesystem operand is specified, statistics for all mounted
filesystems are displayed (subject to the -t option below).
The following options are available:
-a Show all mount points, including those that were mounted with the MNT_IGNORE flag.
-b Use 512-byte blocks rather than the default. Note that this overrides the BLOCKSIZE specification from the environment.
-g Use 1073741824-byte (1-Gbyte) blocks rather than the default. Note that this overrides the BLOCKSIZE specification from the environ-
ment.
-H "Human-readable" output. Use unit suffixes: Byte, Kilobyte, Megabyte, Gigabyte, Terabyte and Petabyte in order to reduce the number
of digits to three or less using base 10 for sizes.
-h "Human-readable" output. Use unit suffixes: Byte, Kilobyte, Megabyte, Gigabyte, Terabyte and Petabyte in order to reduce the number
of digits to three or less using base 2 for sizes.
-i Include statistics on the number of free inodes.
-k Use 1024-byte (1-Kbyte) blocks rather than the default. Note that this overrides the BLOCKSIZE specification from the environment.
-l Only display information about locally-mounted filesystems.
-m Use 1048576-byte (1-Mbyte) blocks rather than the default. Note that this overrides the BLOCKSIZE specification from the environ-
ment.
-n Print out the previously obtained statistics from the filesystems. This option should be used if it is possible that one or more
filesystems are in a state such that they will not be able to provide statistics without a long delay. When this option is speci-
fied, df will not request new statistics from the filesystems, but will respond with the possibly stale statistics that were previ-
ously obtained.
-P Use POSIX compliant output of 512-byte blocks rather than the default. Note that this overrides the BLOCKSIZE specification from the
environment.
-t Only print out statistics for filesystems of the specified types. More than one type may be specified in a comma separated list.
The list of filesystem types can be prefixed with ``no'' to specify the filesystem types for which action should not be taken. For
example, the df command:
df -t nonfs,mfs
lists all filesystems except those of type NFS and MFS. The lsvfs(1) command can be used to find out the types of filesystems that
are available on the system.
ENVIRONMENT
BLOCKSIZE If the environment variable BLOCKSIZE is set, the block counts will be displayed in units of that size block.
BUGS
The -n and -t flags are ignored if a file or filesystem is specified.
SEE ALSO lsvfs(1), quota(1), fstatfs(2), getfsstat(2), statfs(2), getmntinfo(3), fstab(5), mount(8), quot(8)HISTORY
A df command appeared in Version 1 AT&T UNIX.
BSD May 8, 1995 BSD