@ifinfo
This file documents the GNU command line utilities.
-Copyright (C) 1994, 95, 96, 2001 Free Software Foundation, Inc.
+Copyright (C) 1994, 1995, 1996, 2000, 2001 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1 or
@page
@vskip 0pt plus 1filll
-Copyright @copyright{} 1994, 95, 96, 2000 Free Software Foundation, Inc.
+Copyright @copyright{} 1994, 1995, 1996, 2000, 2001 Free Software
+Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1 or
A block size specification can be a positive integer specifying the number
of bytes per block, or it can be @code{human-readable} or @code{si} to
-select a human-readable format.
-
+select a human-readable format. Integers may be followed by suffixes
+that are upward compatible with the
+@uref{http://www.bipm.fr/enus/3_SI/si-prefixes.html, SI prefixes}
+for decimal multiples and with the
+@uref{http://physics.nist.gov/cuu/Units/binary.html, IEC 60027-2
+prefixes for binary multiples}.
With human-readable formats, output sizes are followed by a size letter
such as @samp{M} for megabytes. @code{BLOCK_SIZE=human-readable} uses
powers of 1024; @samp{M} stands for 1,048,576 bytes.
-@code{BLOCK_SIZE=si} is similar, but uses powers of 1000; @samp{M} stands
-for 1,000,000 bytes. (SI, the International System of Units, defines
-these power-of-1000 prefixes.)
-
-An integer block size can be followed by a size letter to specify a
-multiple of that size. When this notation is used, the size letters
-normally stand for powers of 1024, and can be followed by an optional
-@samp{B} for ``byte''; but if followed by @samp{D} (for ``decimal
-byte''), they stand for powers of 1000. For example,
-@code{BLOCK_SIZE=4MB} is equivalent to @code{BLOCK_SIZE=4194304}, and
-@code{BLOCK_SIZE=4MD} is equivalent to @code{BLOCK_SIZE=4000000}.
-
-The following size letters are defined. Large sizes like @code{1Y}
+@code{BLOCK_SIZE=si} is similar, but uses powers of 1000 and appends
+@samp{B}; @samp{MB} stands for 1,000,000 bytes.
+
+An integer block size can be followed by a suffix to specify a
+multiple of that size; in this case an omitted integer is understood
+to be 1. A bare size letter, or one followed by @samp{iB}, specifies
+a multiple using powers of 1024. A size letter followed by @samp{B}
+specifies powers of 1000 instead. For example, @samp{M} and
+@samp{MiB} are equivalent to @samp{1048576}, whereas @samp{MB} is
+equivalent to @samp{1000000}.
+
+The following suffixes are defined. Large sizes like @code{1Y}
may be rejected by your computer due to limitations of its arithmetic.
@table @samp
+@item kB
+@cindex kilobyte, definition of
+kilobyte: @math{10^3 = 1000}.
@item k
-kilo: @math{2^10 = 1024} for @code{human-readable},
-or @math{10^3 = 1000} for @code{si}.
+@itemx K
+@itemx KiB
+@cindex kibibyte, definition of
+kibibyte: @math{2^10 = 1024}. @samp{K} is special: the SI prefix is
+@samp{k} and the IEC 60027-2 prefix is @samp{Ki}, but tradition and
+@sc{posix} use @samp{k} to mean @samp{KiB}.
+@item MB
+@cindex megabyte, definition of
+megabyte: @math{10^6 = 1,000,000}.
@item M
-Mega: @math{2^20 = 1,048,576}
-or @math{10^6 = 1,000,000}.
+@itemx MiB
+@cindex mebibyte, definition of
+mebibyte: @math{2^20 = 1,048,576}.
+@item GB
+@cindex gigabyte, definition of
+gigabyte: @math{10^9 = 1,000,000,000}.
@item G
-Giga: @math{2^30 = 1,073,741,824}
-or @math{10^9 = 1,000,000,000}.
+@itemx GiB
+@cindex gibibyte, definition of
+gibibyte: @math{2^30 = 1,073,741,824}.
+@item TB
+@cindex terabyte, definition of
+terabyte: @math{10^12 = 1,000,000,000,000}.
@item T
-Tera: @math{2^40 = 1,099,511,627,776}
-or @math{10^12 = 1,000,000,000,000}.
+@itemx TiB
+@cindex tebibyte, definition of
+tebibyte: @math{2^40 = 1,099,511,627,776}.
+@item PB
+@cindex petabyte, definition of
+petabyte: @math{10^15 = 1,000,000,000,000,000}.
@item P
-Peta: @math{2^50 = 1,125,899,906,842,624}
-or @math{10^15 = 1,000,000,000,000,000}.
+@itemx PiB
+@cindex pebibyte, definition of
+pebibyte: @math{2^50 = 1,125,899,906,842,624}.
+@item EB
+@cindex exabyte, definition of
+exabyte: @math{10^18 = 1,000,000,000,000,000,000}.
@item E
-Exa: @math{2^60 = 1,152,921,504,606,846,976}@*
-or @math{10^18 = 1,000,000,000,000,000,000}.
+@itemx EiB
+@cindex exbibyte, definition of
+exbibyte: @math{2^60 = 1,152,921,504,606,846,976}.
+@item ZB
+@cindex zettabyte, definition of
+zettabyte: @math{10^21 = 1,000,000,000,000,000,000,000}
@item Z
-Zetta: @math{2^70 = 1,180,591,620,717,411,303,424}@*
-or @math{10^21 = 1,000,000,000,000,000,000,000}.
+@itemx ZiB
+@math{2^70 = 1,180,591,620,717,411,303,424}.
+(@samp{Zi} is a GNU extension to IEC 60027-2.)
+@item YB
+@cindex yottabyte, definition of
+yottabyte: @math{10^24 = 1,000,000,000,000,000,000,000,000}.
@item Y
-Yotta: @math{2^80 = 1,208,925,819,614,629,174,706,176}@*
-or @math{10^24 = 1,000,000,000,000,000,000,000,000}.
+@itemx YiB
+@math{2^80 = 1,208,925,819,614,629,174,706,176}.
+(@samp{Yi} is a GNU extension to IEC 60027-2.)
@end table
@opindex -k
-@opindex --kilobytes
@opindex -h
+@opindex --block-size
@opindex --human-readable
@opindex --si
Block size defaults can be overridden by an explicit
-@option{--block-size=@var{size}} option. The @option{-k} or
-@option{--kilobytes} option is equivalent to @option{--block-size=1k}, which
+@option{--block-size=@var{size}} option. The @option{-k}
+option is equivalent to @option{--block-size=1K}, which
is the default unless the @env{POSIXLY_CORRECT} environment variable is
set. The @option{-h} or @option{--human-readable} option is equivalent to
@option{--block-size=human-readable}. The @option{--si} option is
@opindex --buffer-size
@cindex size for main memory sorting
Use a main-memory sort buffer of the given @var{size}. By default,
-@var{size} is in units of 1,024 bytes. Appending @samp{%} causes
+@var{size} is in units of 1024 bytes. Appending @samp{%} causes
@var{size} to be interpreted as a percentage of physical memory.
-Appending @samp{k} multiplies @var{size} by 1,024 (the default),
+Appending @samp{K} multiplies @var{size} by 1024 (the default),
@samp{M} by 1,048,576, @samp{G} by 1,073,741,824, and so on for
@samp{T}, @samp{P}, @samp{E}, @samp{Z}, and @samp{Y}. Appending
@samp{b} causes @var{size} to be interpreted as a byte count, with no
@opindex -h
@opindex --human-readable
@cindex human-readable output
-Append a size letter such as @samp{M} for megabytes to each size.
+Append a size letter to each size, such as @samp{M} for mebibytes.
Powers of 1024 are used, not 1000; @samp{M} stands for 1,048,576 bytes.
Use the @option{--si} option if you prefer powers of 1000.
@itemx --si
@opindex --si
@cindex SI output
-Append a size letter such as @samp{M} for megabytes to each size. (SI
-is the International System of Units, which defines these letters as
-prefixes.) Powers of 1000 are used, not 1024; @samp{M} stands for
+Append an SI-style abbreviation to each size, such as @samp{MB} for
+megabytes. Powers of 1000 are used, not 1024; @samp{MB} stands for
1,000,000 bytes. Use the @option{-h} or @option{--human-readable} option if
you prefer powers of 1024.
@end table
@item -k
-@itemx --kilobytes
@opindex -k
-@opindex --kilobytes
Print file sizes in 1024-byte blocks, overriding the default block
size (@pxref{Block size}).
+This option is equivalent to @option{--block-size=1K}.
@item -m
@itemx --format=commas
Use different @command{dd} invocations to use different block sizes for
skipping and I/O. For example, the following shell commands copy data
-in 512 kB blocks between a disk and a tape, but do not save or restore a
-4 kB label at the start of the disk:
+in 512 KiB blocks between a disk and a tape, but do not save or restore a
+4 KiB label at the start of the disk:
@example
disk=/dev/rdsk/c0t1d0s2
@cindex size of file to shred
Shred the first @var{BYTES} bytes of the file. The default is to shred
the whole file. @var{BYTES} can be followed by a size specification like
-@samp{k}, @samp{M}, or @samp{G} to specify a multiple. @xref{Block size}.
+@samp{K}, @samp{M}, or @samp{G} to specify a multiple. @xref{Block size}.
@item -u
@itemx --remove
You might use the following command to erase all trace of the
file system you'd created on the floppy disk in your first drive.
-That command takes about 20 minutes to erase a 1.44MB floppy.
+That command takes about 20 minutes to erase a ``1.44MB'' (actually
+1440 KiB) floppy.
@example
shred --verbose /dev/fd0
type ``ignore'' or ``auto'', supported by some operating systems, are
only included if this option is specified.
+@item -B @var{size}
+@itemx --block-size=@var{size}
+@opindex -B
+@opindex --block-size
+@cindex filesystem sizes
+Scale sizes by @var{size} before printing them (@pxref{Block size}).
+For example, @option{-BG} prints sizes in units of 1,073,741,824 bytes.
+
@item -h
@itemx --human-readable
@opindex -h
@opindex --human-readable
@cindex human-readable output
-Append a size letter such as @samp{M} for megabytes to each size.
+Append a size letter to each size, such as @samp{M} for mebibytes.
Powers of 1024 are used, not 1000; @samp{M} stands for 1,048,576 bytes.
Use the @option{-H} or @option{--si} option if you prefer powers of 1000.
@opindex -H
@opindex --si
@cindex SI output
-Append a size letter such as @samp{M} for megabytes to each size. (SI
-is the International System of Units, which defines these letters as
-prefixes.) Powers of 1000 are used, not 1024; @samp{M} stands for
+Append an SI-style abbreviation to each size, such as @samp{MB} for
+megabytes. Powers of 1000 are used, not 1024; @samp{MB} stands for
1,000,000 bytes. Use the @option{-h} or @option{--human-readable} option if
you prefer powers of 1024.
permissions, timestamps, and location on the disk.
@item -k
-@itemx --kilobytes
@opindex -k
-@opindex --kilobytes
-@cindex kilobytes for filesystem sizes
+@cindex kibibytes for filesystem sizes
Print sizes in 1024-byte blocks, overriding the default block size
(@pxref{Block size}).
+This option is equivalent to @option{--block-size=1K}.
@item -l
@itemx --local
Limit the listing to local filesystems. By default, remote filesystems
are also listed.
-@item -m
-@itemx --megabytes
-@opindex -m
-@opindex --megabytes
-@cindex megabytes for filesystem sizes
-Print sizes in megabyte (that is, 1,048,576-byte) blocks.
-
@item --no-sync
@opindex --no-sync
@cindex filesystem space, retrieving old data more quickly
@opindex --bytes
Print sizes in bytes, overriding the default block size (@pxref{Block size}).
+@item -B @var{size}
+@itemx --block-size=@var{size}
+@opindex -B
+@opindex --block-size
+@cindex file sizes
+Scale sizes by @var{size} before printing them (@pxref{Block size}).
+For example, @option{-BG} prints sizes in units of 1,073,741,824 bytes.
+
@item -c
@itemx --total
@opindex -c
@opindex -h
@opindex --human-readable
@cindex human-readable output
-Append a size letter such as @samp{M} for megabytes to each size.
+Append a size letter to each size, such as @samp{M} for mebibytes.
Powers of 1024 are used, not 1000; @samp{M} stands for 1,048,576 bytes.
Use the @option{-H} or @option{--si} option if you prefer powers of 1000.
@opindex -H
@opindex --si
@cindex SI output
-Append a size letter such as @samp{M} for megabytes to each size. (SI
-is the International System of Units, which defines these letters as
-prefixes.) Powers of 1000 are used, not 1024; @samp{M} stands for
+Append an SI-style abbreviation to each size, such as @samp{MB} for
+megabytes. Powers of 1000 are used, not 1024; @samp{MB} stands for
1,000,000 bytes. Use the @option{-h} or @option{--human-readable} option if
you prefer powers of 1024.
@item -k
-@itemx --kilobytes
@opindex -k
-@opindex --kilobytes
+@cindex kibibytes for file sizes
Print sizes in 1024-byte blocks, overriding the default block size
(@pxref{Block size}).
+This option is equivalent to @option{--block-size=1K}.
@item -l
@itemx --count-links
most MAX_DEPTH levels down from the root of the hierarchy. The root
is at level 0, so @code{du --max-depth=0} is equivalent to @code{du -s}.
-@item -m
-@itemx --megabytes
-@opindex -m
-@opindex --megabytes
-@cindex megabytes for filesystem sizes
-Print sizes in megabyte (that is, 1,048,576-byte) blocks.
-
@item -s
@itemx --summarize
@opindex -s
projects / thirdparty / coreutils.git / commitdiff
