* chmod: (coreutils)chmod invocation. Change file permissions.
* chown: (coreutils)chown invocation. Change file owners/groups.
* chroot: (coreutils)chroot invocation. Specify the root directory.
-* cksum: (coreutils)cksum invocation. Print @sc{posix} CRC checksum.
+* cksum: (coreutils)cksum invocation. Print @acronym{POSIX} CRC checksum.
* comm: (coreutils)comm invocation. Compare sorted files by line.
* cp: (coreutils)cp invocation. Copy files.
* csplit: (coreutils)csplit invocation. Split by context.
please get involved in improving this manual. The entire @sc{gnu} community
will benefit.
-@cindex @sc{posix}
+@cindex @acronym{POSIX}
The @sc{gnu} utilities documented here are mostly compatible with the
-@sc{posix} standard.
+@acronym{POSIX} standard.
@cindex bugs, reporting
Please report bugs to @email{bug-coreutils@@gnu.org}. Remember
to include the version number, machine architecture, input files, and
* Block size:: BLOCK_SIZE and --block-size, in some programs.
* Target directory:: --target-directory, in some programs.
* Trailing slashes:: --strip-trailing-slashes, in some programs.
-* Standards conformance:: Conformance to the @sc{posix} standard.
+* Standards conformance:: Conformance to the @acronym{POSIX} standard.
@end menu
@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}.
+@acronym{POSIX} use @samp{k} to mean @samp{KiB}.
@item MB
@cindex megabyte, definition of
megabyte: @math{10^6 = 1,000,000}.
interpret a trailing slash as a request to dereference the symbolic link
and so must rename the indirectly referenced @emph{directory} and not
the symbolic link. Although it may seem surprising that such behavior
-be the default, it is required by @sc{posix} and is consistent with
+be the default, it is required by @acronym{POSIX} and is consistent with
other parts of that standard.
@node Standards conformance
@vindex POSIXLY_CORRECT
In a few cases, the @sc{gnu} utilities' default behavior is
-incompatible with the @sc{posix} standard. To suppress these
+incompatible with the @acronym{POSIX} standard. To suppress these
incompatibilities, define the @env{POSIXLY_CORRECT} environment
-variable. Unless you are checking for @sc{posix} conformance, you
+variable. Unless you are checking for @acronym{POSIX} conformance, you
probably do not need to define @env{POSIXLY_CORRECT}.
-Newer versions of @sc{posix} are occasionally incompatible with older
-versions. For example, older versions of @sc{posix} required the
+Newer versions of @acronym{POSIX} are occasionally incompatible with older
+versions. For example, older versions of @acronym{POSIX} required the
command @samp{sort +1} to sort based on the second and succeeding
-fields in each input line, but starting with @sc{posix} 1003.1-2001
+fields in each input line, but starting with @acronym{POSIX} 1003.1-2001
the same command is required to sort the file named @file{+1}, and you
must instead use the command @samp{sort -k 2} to get the field-based
sort.
@vindex _POSIX2_VERSION
-The @sc{gnu} utilities normally conform to the version of @sc{posix}
+The @sc{gnu} utilities normally conform to the version of @acronym{POSIX}
that is standard for your system. To cause them to conform to a
-different version of @sc{posix}, define the @env{_POSIX2_VERSION}
+different version of @acronym{POSIX}, define the @env{_POSIX2_VERSION}
environment variable to a value of the form @var{yyyymm} specifying
the year and month the standard was adopted. Two values are currently
supported for @env{_POSIX2_VERSION}: @samp{199209} stands for
-@sc{posix} 1003.2-1992, and @samp{200112} stands for @sc{posix}
+@acronym{POSIX} 1003.2-1992, and @samp{200112} stands for @acronym{POSIX}
1003.1-2001. For example, if you are running older software that
-assumes an older version of @sc{posix} and uses @samp{sort +1}, you
+assumes an older version of @acronym{POSIX} and uses @samp{sort +1}, you
can work around the compatibility problems by setting
@samp{_POSIX2_VERSION=199209} in your environment.
@opindex --strings
@cindex string constants, outputting
Instead of the normal output, output only @dfn{string constants}: at
-least @var{n} consecutive @sc{ascii} graphic characters,
+least @var{n} consecutive @acronym{ASCII} graphic characters,
followed by a null (zero) byte.
If @var{n} is omitted with @option{--strings}, the default is 3. On
older systems, @sc{gnu} @command{od} instead supports an obsolete
option @option{-s[@var{n}]}, where @var{n} also defaults to 3.
-@sc{posix} 1003.1-2001 (@pxref{Standards conformance}) does not allow
+@acronym{POSIX} 1003.1-2001 (@pxref{Standards conformance}) does not allow
@option{-s} without an argument; use @option{--strings} instead.
@item -t @var{type}
in the order that you specified.
Adding a trailing ``z'' to any type specification appends a display
-of the @sc{ascii} character representation of the printable characters
+of the @acronym{ASCII} character representation of the printable characters
to the output line generated by the type specification.
@table @samp
@item a
named character
@item c
-@sc{ascii} character or backslash escape,
+@acronym{ASCII} character or backslash escape,
@item d
signed decimal
@item f
If this option is not given at all, the default is 16. If @var{n} is
omitted with @option{--width}, the default is 32. On older systems,
@sc{gnu} @command{od} instead supports an obsolete option
-@option{-w[@var{n}]}, where @var{n} also defaults to 32. @sc{posix}
+@option{-w[@var{n}]}, where @var{n} also defaults to 32. @acronym{POSIX}
1003.1-2001 (@pxref{Standards conformance}) does not allow @option{-w}
without an argument; use @option{--width} instead.
@item -c
@opindex -c
-Output as @sc{ascii} characters or backslash escapes. Equivalent to
+Output as @acronym{ASCII} characters or backslash escapes. Equivalent to
@option{-tc}.
@item -d
@item
Some small @var{letter options} (@option{-s}, @option{-w}) have been
-redefined for better @sc{posix} compliance. The output of some further
+redefined for better @acronym{POSIX} compliance. The output of some further
cases has been adapted to other Unix systems. These changes are not
compatible with earlier versions of the program.
@item
Some of the option-arguments (compare @option{-s}, @option{-e},
@option{-i}, @option{-n}) cannot be specified as separate arguments from the
-preceding option letter (already stated in the @sc{posix} specification).
+preceding option letter (already stated in the @acronym{POSIX} specification).
@end itemize
The program accepts the following options. Also see @ref{Common options}.
no column alignment used; may be used with
@option{--sep-string[=@var{string}]}. @option{-J} has been introduced
(together with @option{-W} and @option{--sep-string})
-to disentangle the old (@sc{posix}-compliant) options @option{-w} and
+to disentangle the old (@acronym{POSIX}-compliant) options @option{-w} and
@option{-s} along with the three column options.
printed with single column output only. The @var{TAB}-width varies
with the @var{TAB}-position, e.g. with the left @var{margin} specified
by @option{-o} option. With multicolumn output priority is given to
-@samp{equal width of output columns} (a @sc{posix} specification).
+@samp{equal width of output columns} (a @acronym{POSIX} specification).
The @var{TAB}-width is fixed to the value of the first column and does
not change with different values of left @var{margin}. That means a
fixed number of spaces is always printed in the place of the
character} with @option{-w}. Without @option{-s} the default separator
@samp{space} is set. @option{-s[char]} turns off line truncation of all
three column options (@option{-COLUMN}|@option{-a -COLUMN}|@option{-m}) unless
-@option{-w} is set. This is a @sc{posix}-compliant formulation.
+@option{-w} is set. This is a @acronym{POSIX}-compliant formulation.
@item -S @var{string}
@var{string} is equivalent to @option{--sep-string=""}.
On older systems, @command{pr} instead supports an obsolete option
-@option{-S[@var{string}]}, where @var{string} is optional. @sc{posix}
+@option{-S[@var{string}]}, where @var{string} is optional. @acronym{POSIX}
1003.1-2001 (@pxref{Standards conformance}) does not allow this older
usage. To specify an empty @var{string} portably, use
@option{--sep-string}.
off the default page width and any line truncation and column alignment.
Lines of full length are merged, regardless of the column options
set. No @var{page_width} setting is possible with single column output.
-A @sc{posix}-compliant formulation.
+A @acronym{POSIX}-compliant formulation.
@item -W @var{page_width}
@itemx --page_width=@var{page_width}
Use a maximum line length of @var{width} columns instead of 80.
On older systems, @command{fold} supports an obsolete option
-@option{-@var{width}}. @sc{posix} 1003.1-2001 (@pxref{Standards
+@option{-@var{width}}. @acronym{POSIX} 1003.1-2001 (@pxref{Standards
conformance}) does not allow this; use @option{-w @var{width}}
instead.
specified first. @var{count} is a decimal number optionally followed
by a size letter (@samp{b}, @samp{k}, @samp{m}) as in @code{-c}, or
@samp{l} to mean count by lines, or other option letters (@samp{cqv}).
-@sc{posix} 1003.1-2001 (@pxref{Standards conformance}) does not allow
+@acronym{POSIX} 1003.1-2001 (@pxref{Standards conformance}) does not allow
this; use @option{-c @var{count}} or @option{-n @var{count}} instead.
@node tail invocation
@samp{l} to mean count by lines, or other option letters
(@samp{cfqv}). Some older @command{tail} implementations also support
an obsolete option @option{+@var{count}} with the same meaning as
-@option{-+@var{count}}. @sc{posix} 1003.1-2001 (@pxref{Standards
+@option{-+@var{count}}. @acronym{POSIX} 1003.1-2001 (@pxref{Standards
conformance}) does not allow these options; use @option{-c
@var{count}} or @option{-n @var{count}} instead.
Put @var{lines} lines of @var{input} into each output file.
On older systems, @command{split} supports an obsolete option
-@option{-@var{lines}}. @sc{posix} 1003.1-2001 (@pxref{Standards
+@option{-@var{lines}}. @acronym{POSIX} 1003.1-2001 (@pxref{Standards
conformance}) does not allow this; use @option{-l @var{lines}}
instead.
counts are printed in this order: newlines, words, characters, bytes.
By default, each count is output right-justified in a 7-byte field with
one space between fields so that the numbers and file names line up nicely
-in columns. However, @sc{posix} requires that there be exactly one space
-separating columns. You can make @code{wc} use the @sc{posix}-mandated
+in columns. However, @acronym{POSIX} requires that there be exactly one space
+separating columns. You can make @code{wc} use the @acronym{POSIX}-mandated
output format by setting the @env{POSIXLY_CORRECT} environment variable.
By default, @code{wc} prints three counts: the newline, words, and byte
@command{cksum} output for the original files (typically given in the
distribution).
-The CRC algorithm is specified by the @sc{posix} standard. It is not
+The CRC algorithm is specified by the @acronym{POSIX} standard. It is not
compatible with the BSD or System V @command{sum} algorithms (see the
previous section); it is more robust.
ordering options, until a difference is found or no fields are left.
Unless otherwise specified, all comparisons use the character collating
sequence specified by the @env{LC_COLLATE} locale. @footnote{If you
-use a non-@sc{posix} locale (e.g., by setting @env{LC_ALL}
+use a non-@acronym{POSIX} locale (e.g., by setting @env{LC_ALL}
to @samp{en_US}), then @command{sort} may produce output that is sorted
differently than you're accustomed to. In that case, set the @env{LC_ALL}
environment variable to @samp{C}. Note that setting only @env{LC_COLLATE}
specified globally or as part of a specific key field. If no key
fields are specified, global options apply to comparison of entire
lines; otherwise the global options are inherited by key fields that do
-not specify any special options of their own. In pre-@sc{posix}
+not specify any special options of their own. In pre-@acronym{POSIX}
versions of @command{sort}, global options affect only later key fields,
so portable shell scripts should specify global options first.
@opindex -z
@opindex --zero-terminated
@cindex sort zero-terminated lines
-Treat the input as a set of lines, each terminated by a zero byte (@sc{ascii}
-@sc{nul} (Null) character) instead of an @sc{ascii} @sc{lf} (Line Feed).
+Treat the input as a set of lines, each terminated by a zero byte
+(@acronym{ASCII} @sc{nul} (Null) character) instead of an
+@acronym{ASCII} @sc{lf} (Line Feed).
This option can be useful in conjunction with @samp{perl -0} or
@samp{find -print0} and @samp{xargs -0} which do the same in order to
reliably handle arbitrary pathnames (even those which contain Line Feed
Historical (BSD and System V) implementations of @command{sort} have
differed in their interpretation of some options, particularly
-@option{-b}, @option{-f}, and @option{-n}. @sc{gnu} sort follows the @sc{posix}
+@option{-b}, @option{-f}, and @option{-n}. @sc{gnu} sort follows the @acronym{POSIX}
behavior, which is usually (but not always!) like the System V behavior.
-According to @sc{posix}, @option{-n} no longer implies @option{-b}. For
+According to @acronym{POSIX}, @option{-n} no longer implies @option{-b}. For
consistency, @option{-M} has been changed in the same way. This may
affect the meaning of character positions in field specifications in
obscure cases. The only fix is to add an explicit @option{-b}.
On older systems, @command{sort} supports an obsolete origin-zero
syntax @samp{+@var{pos1} [-@var{pos2}]} for specifying sort keys.
-@sc{posix} 1003.1-2001 (@pxref{Standards conformance}) does not allow
+@acronym{POSIX} 1003.1-2001 (@pxref{Standards conformance}) does not allow
this; use @option{-k} instead.
Here are some examples to illustrate various combinations of options.
each other by at least one space or tab.
On older systems, @command{uniq} supports an obsolete option
-@option{-@var{n}}. @sc{posix} 1003.1-2001 (@pxref{Standards conformance})
+@option{-@var{n}}. @acronym{POSIX} 1003.1-2001 (@pxref{Standards conformance})
does not allow this; use @option{-f @var{n}} instead.
@item -s @var{n}
the field and character skipping options, fields are skipped over first.
On older systems, @command{uniq} supports an obsolete option
-@option{+@var{n}}. @sc{posix} 1003.1-2001 (@pxref{Standards conformance})
+@option{+@var{n}}. @acronym{POSIX} 1003.1-2001 (@pxref{Standards conformance})
does not allow this; use @option{-s @var{n}} instead.
@item -c
using 8-bit ISO 8859-1 code, also known as Latin-1 character set,
@emph{unless} it is compiled for MS-DOS, in which case it uses the
character set of the IBM-PC. (@sc{gnu} @command{ptx} is not known to work on
-smaller MS-DOS machines anymore.) Compared to 7-bit @sc{ascii}, the set
+smaller MS-DOS machines anymore.) Compared to 7-bit @acronym{ASCII}, the set
of characters which are letters is different; this alters the behavior
of regular expression matching. Thus, the default regular expression
for a keyword allows foreign or diacriticized letters. Keyword sorting,
@code{~\@{ @}} respectively. Other diacriticized characters of the
underlying character set produce an appropriate @TeX{} sequence as far
as possible. The other non-graphical characters, like newline and tab,
-and all other characters which are not part of @sc{ascii}, are merely
+and all other characters which are not part of @acronym{ASCII}, are merely
changed to exactly one space, with no special attempt to compress
consecutive spaces. Let me know how to improve this special character
processing for @TeX{}.
(using either of the @option{-a} or @option{-v} options), there is no way
to specify the join field using @var{m.n} in @var{field-list}
if there are unpairable lines in both files.
-To give @command{join} that functionality, @sc{posix} invented the @samp{0}
+To give @command{join} that functionality, @acronym{POSIX} invented the @samp{0}
field specification notation.
The elements in @var{field-list}
as well as digits.
Many historically common and even accepted uses of ranges are not
-portable. For example, on @sc{ebcdic} hosts using the @samp{A-Z}
+portable. For example, on @acronym{EBCDIC} hosts using the @samp{A-Z}
range will not do what most would expect because @samp{A} through @samp{Z}
-are not contiguous as they are in @sc{ascii}.
-If you can rely on a @sc{posix} compliant version of @command{tr}, then
+are not contiguous as they are in @acronym{ASCII}.
+If you can rely on a @acronym{POSIX} compliant version of @command{tr}, then
the best way to work around this is to use character classes (see below).
Otherwise, it is most portable (and most ugly) to enumerate the members
of the ranges.
@var{set2}, the extra characters at the end of @var{set2} are ignored.
On the other hand, making @var{set1} longer than @var{set2} is not
-portable; @sc{posix} says that the result is undefined. In this situation,
+portable; @acronym{POSIX} says that the result is undefined. In this situation,
BSD @command{tr} pads @var{set2} to the length of @var{set1} by repeating
the last character of @var{set2} as many times as necessary. System V
@command{tr} truncates @var{set1} to the length of @var{set2}.
@noindent
By the way, the above idiom is not portable because it uses ranges.
-Assuming a @sc{posix} compliant @command{tr}, here is a better way to write it:
+Assuming a @acronym{POSIX} compliant @command{tr}, here is a better way to write it:
@example
tr -cs '[:alnum:]' '[\n*]'
@vindex POSIXLY_CORRECT
Setting the environment variable @env{POSIXLY_CORRECT} turns off the
following warning and error messages, for strict compliance with
-@sc{posix}. Otherwise, the following diagnostics are issued:
+@acronym{POSIX}. Otherwise, the following diagnostics are issued:
@enumerate
When the @option{--delete} option is given but @option{--squeeze-repeats}
is not, and @var{set2} is given, @sc{gnu} @command{tr} by default prints
a usage message and exits, because @var{set2} would not be used.
-The @sc{posix} specification says that @var{set2} must be ignored in
+The @acronym{POSIX} specification says that @var{set2} must be ignored in
this case. Silently ignoring arguments is a bad idea.
@item
@end enumerate
@sc{gnu} @command{tr} does not provide complete BSD or System V compatibility.
-For example, it is impossible to disable interpretation of the @sc{posix}
+For example, it is impossible to disable interpretation of the @acronym{POSIX}
constructs @samp{[:alpha:]}, @samp{[=c=]}, and @samp{[c*10]}. Also, @sc{gnu}
@command{tr} does not delete zero bytes automatically, unlike traditional
Unix versions, which provide no way to preserve zero bytes.
On older systems, @command{expand} supports an obsolete option
@option{-@var{tab1}[,@var{tab2}]@dots{}}, where tabstops must be
-separated by commas. @sc{posix} 1003.1-2001 (@pxref{Standards
+separated by commas. @acronym{POSIX} 1003.1-2001 (@pxref{Standards
conformance}) does not allow this; use @option{-t
@var{tab1}[,@var{tab2}]@dots{}} instead.
On older systems, @command{unexpand} supports an obsolete option
@option{-@var{tab1}[,@var{tab2}]@dots{}}, where tabstops must be
separated by commas. (Unlike @option{-t}, this obsolete option does
-not imply @option{-a}.) @sc{posix} 1003.1-2001 (@pxref{Standards
+not imply @option{-a}.) @acronym{POSIX} 1003.1-2001 (@pxref{Standards
conformance}) does not allow this; use @option{--first-only -t
@var{tab1}[,@var{tab2}]@dots{}} instead.
@vindex LC_ALL
By default, the output is sorted alphabetically, according to the locale
-settings in effect. @footnote{If you use a non-@sc{posix}
+settings in effect. @footnote{If you use a non-@acronym{POSIX}
locale (e.g., by setting @env{LC_ALL} to @samp{en_US}), then @command{ls} may
produce output that is sorted differently than you're accustomed to.
In that case, set the @env{LC_ALL} environment variable to @samp{C}.}
@cindex sorting @command{ls} output
These options change the order in which @command{ls} sorts the information
-it outputs. By default, sorting is done by character code (e.g., ASCII
-order).
+it outputs. By default, sorting is done by character code
+(e.g., @acronym{ASCII} order).
@table @samp
@table @samp
@item full-iso
List timestamps in full, rather than using the standard abbreviation
-heuristics. The format is @sc{iso} 8601 date, time, and time zone
+heuristics. The format is @acronym{ISO} 8601 date, time, and time zone
format with nanosecond precision, e.g., @samp{2001-05-14
23:45:56.477817180 -0700}. It's not possible to change the format, but
you can extract out the date string with @command{cut} and then pass the
when you have a Makefile that is not regenerating files properly.
@item iso
-Use @sc{iso}-style time stamps like @samp{2001-05-14@ } and @samp{05-14
+Use @acronym{ISO}-style time stamps like @samp{2001-05-14@ } and @samp{05-14
23:45}.
@item locale
set.
@item posix-iso
-Use traditional @sc{posix}-locale dates like @samp{May 14@ @ 2001} and
-@samp{May 14 23:45} unless the user specifies a non-@sc{posix} locale,
-in which case use @sc{iso}-style dates. This is the default.
+Use traditional @acronym{POSIX}-locale dates like @samp{May 14@ @ 2001} and
+@samp{May 14 23:45} unless the user specifies a non-@acronym{POSIX} locale,
+in which case use @acronym{ISO}-style dates. This is the default.
@item +@var{format}
Use @var{format} for dates, where @var{format} is interpreted like the
@vindex TIME_STYLE
You can specify the default value of the @option{--time-style} option
with the environment variable @env{TIME_STYLE}. @sc{gnu} Emacs 21 and
-later can parse @sc{iso} dates, but older Emacs versions do not, so if
-you are using an older version of Emacs and specify a non-@sc{posix}
+later can parse @acronym{ISO} dates, but older Emacs versions do not, so if
+you are using an older version of Emacs and specify a non-@acronym{POSIX}
locale, you may need to set @samp{TIME_STYLE="locale"}.
non-@sc{gnu} systems, @option{-r} implies the equivalent of
@option{-L} and @option{--copy-contents} for historical reasons.
Also, it is not portable to use @option{-R} to copy symbolic links
-unless you also specify @option{-P}, as @sc{posix} allows
+unless you also specify @option{-P}, as @acronym{POSIX} allows
implementations that dereference symbolic links by default.
@item --remove-destination
@item ascii
@opindex ascii@r{, converting to}
-Convert EBCDIC to ASCII.
+Convert @acronym{EBCDIC} to @acronym{ASCII}.
@item ebcdic
@opindex ebcdic@r{, converting to}
-Convert ASCII to EBCDIC.
+Convert @acronym{ASCII} to @acronym{EBCDIC}.
@item ibm
@opindex alternate ebcdic@r{, converting to}
-Convert ASCII to alternate EBCDIC.
+Convert @acronym{ASCII} to alternate @acronym{EBCDIC}.
@item block
@opindex block @r{(space-padding)}
file---indeed, it is not incorrect to say that the inode @emph{is} the
file. On all existing implementations, you cannot make a hard link to
a directory, and hard links cannot cross filesystem boundaries. (These
-restrictions are not mandated by @sc{posix}, however.)
+restrictions are not mandated by @acronym{POSIX}, however.)
@cindex dereferencing symbolic links
@cindex symbolic link, defined
option and no timestamp is given with any of the @option{-d}, @option{-r},
or @option{-t} options and the @samp{--} argument is not given, that
argument is interpreted as the time for the other files instead of
-as a file name. @sc{posix} 1003.1-2001 (@pxref{Standards conformance})
+as a file name. @acronym{POSIX} 1003.1-2001 (@pxref{Standards conformance})
does not allow this; use @option{-t} instead.
@cindex empty files, creating
@opindex -P
@opindex --portability
@cindex one-line output format
-@cindex @sc{posix} output format
+@cindex @acronym{POSIX} output format
@cindex portable output format
@cindex output format, portable
-Use the @sc{posix} output format. This is like the default format except
+Use the @acronym{POSIX} output format. This is like the default format except
for the following:
@enumerate
rounded to the nearest integer.
@item
-The labels in the header output line are changed to conform to @sc{posix}.
+The labels in the header output line are changed to conform to @acronym{POSIX}.
@end enumerate
@item --sync
@item \\
backslash
@item \@var{nnn}
-the character whose ASCII code is @var{nnn} (octal); if @var{nnn} is not
+the character whose @acronym{ASCII} code is @var{nnn} (octal); if @var{nnn} is not
a valid octal number, it is printed literally.
@end table
@command{printf}.
For larger strings, you don't need to look up the hexadecimal code
-values of each character one by one. ASCII characters mixed with \u
+values of each character one by one. @acronym{ASCII} characters mixed with \u
escape sequences is also known as the JAVA source file encoding. You can
use GNU recode 3.5c (or newer) to convert strings to this encoding. Here
is how to convert a piece of text into a shell script which will output
where an unsuccessful command is needed.
By default, @command{false} honors the @option{--help} and @option{--version}
-options. However, that is contrary to @sc{posix}, so when the environment
+options. However, that is contrary to @acronym{POSIX}, so when the environment
variable @env{POSIXLY_CORRECT} is set, @command{false} ignores @emph{all}
command line arguments, including @option{--help} and @option{--version}.
command, not the one documented here.
By default, @command{true} honors the @option{--help} and @option{--version}
-options. However, that is contrary to @sc{posix}, so when the environment
+options. However, that is contrary to @acronym{POSIX}, so when the environment
variable @env{POSIXLY_CORRECT} is set, @command{true} ignores @emph{all}
command line arguments, including @option{--help} and @option{--version}.
In the regular expression, @code{\+}, @code{\?}, and @code{\|} are
operators which respectively match one or more, zero or one, or separate
alternatives. SunOS and other @command{expr}'s treat these as regular
-characters. (@sc{posix} allows either behavior.)
+characters. (@acronym{POSIX} allows either behavior.)
@xref{Top, , Regular Expression Library, regex, Regex}, for details of
regular expression syntax. Some examples are in @ref{Examples of expr}.
@opindex --portability
Instead of performing length checks on the underlying filesystem,
test the length of each file name and its components against the
-@sc{posix} minimum limits for portability. Also check that the file
+@acronym{POSIX} minimum limits for portability. Also check that the file
name contains no characters not in the portable file name character set.
@end table
@opindex --file
Set the line opened by the filename specified in @var{device} instead of
the tty line connected to standard input. This option is necessary
-because opening a @sc{posix} tty requires use of the @code{O_NONDELAY} flag to
-prevent a @sc{posix} tty from blocking until the carrier detect line is high if
+because opening a @acronym{POSIX} tty requires use of the @code{O_NONDELAY} flag to
+prevent a @acronym{POSIX} tty from blocking until the carrier detect line is high if
the @code{clocal} flag is not set. Hence, it is not always possible
to allow the shell to open the device in the traditional manner.
case, that is, when @emph{not} negated (unless stated otherwise,
of course).
-Some settings are not available on all @sc{posix} systems, since they use
-extensions. Such arguments are marked below with ``Non-@sc{posix}'' in their
-description. On non-@sc{posix} systems, those or other settings also may not
+Some settings are not available on all @acronym{POSIX} systems, since they use
+extensions. Such arguments are marked below with ``Non-@acronym{POSIX}'' in their
+description. On non-@acronym{POSIX} systems, those or other settings also may not
be available, but it's not feasible to document all the variations: just
try it and see.
@cindex hardware flow control
@cindex flow control, hardware
@cindex RTS/CTS flow control
-Enable RTS/CTS flow control. Non-@sc{posix}. May be negated.
+Enable RTS/CTS flow control. Non-@acronym{POSIX}. May be negated.
@end table
@item iuclc
@opindex iuclc
@cindex uppercase, translating to lowercase
-Translate uppercase characters to lowercase. Non-@sc{posix}. May be
+Translate uppercase characters to lowercase. Non-@acronym{POSIX}. May be
negated.
@item ixany
@opindex ixany
Allow any character to restart output (only the start character
-if negated). Non-@sc{posix}. May be negated.
+if negated). Non-@acronym{POSIX}. May be negated.
@item imaxbel
@opindex imaxbel
@cindex beeping at input buffer full
Enable beeping and not flushing input buffer if a character arrives
-when the input buffer is full. Non-@sc{posix}. May be negated.
+when the input buffer is full. Non-@acronym{POSIX}. May be negated.
@end table
@item olcuc
@opindex olcuc
@cindex lowercase, translating to output
-Translate lowercase characters to uppercase. Non-@sc{posix}. May be
+Translate lowercase characters to uppercase. Non-@acronym{POSIX}. May be
negated.
@item ocrnl
@opindex ocrnl
@cindex return, translating to newline
-Translate carriage return to newline. Non-@sc{posix}. May be negated.
+Translate carriage return to newline. Non-@acronym{POSIX}. May be negated.
@item onlcr
@opindex onlcr
@cindex newline, translating to crlf
-Translate newline to carriage return-newline. Non-@sc{posix}. May be
+Translate newline to carriage return-newline. Non-@acronym{POSIX}. May be
negated.
@item onocr
@opindex onocr
-Do not print carriage returns in the first column. Non-@sc{posix}.
+Do not print carriage returns in the first column. Non-@acronym{POSIX}.
May be negated.
@item onlret
@opindex onlret
-Newline performs a carriage return. Non-@sc{posix}. May be negated.
+Newline performs a carriage return. Non-@acronym{POSIX}. May be negated.
@item ofill
@opindex ofill
@cindex pad instead of timing for delaying
-Use fill (padding) characters instead of timing for delays. Non-@sc{posix}.
+Use fill (padding) characters instead of timing for delays. Non-@acronym{POSIX}.
May be negated.
@item ofdel
@opindex ofdel
@cindex pad character
-Use delete characters for fill instead of null characters. Non-@sc{posix}.
+Use delete characters for fill instead of null characters. Non-@acronym{POSIX}.
May be negated.
@item nl1
@itemx nl0
@opindex nl@var{n}
-Newline delay style. Non-@sc{posix}.
+Newline delay style. Non-@acronym{POSIX}.
@item cr3
@itemx cr2
@itemx cr1
@itemx cr0
@opindex cr@var{n}
-Carriage return delay style. Non-@sc{posix}.
+Carriage return delay style. Non-@acronym{POSIX}.
@item tab3
@itemx tab2
@itemx tab1
@itemx tab0
@opindex tab@var{n}
-Horizontal tab delay style. Non-@sc{posix}.
+Horizontal tab delay style. Non-@acronym{POSIX}.
@item bs1
@itemx bs0
@opindex bs@var{n}
-Backspace delay style. Non-@sc{posix}.
+Backspace delay style. Non-@acronym{POSIX}.
@item vt1
@itemx vt0
@opindex vt@var{n}
-Vertical tab delay style. Non-@sc{posix}.
+Vertical tab delay style. Non-@acronym{POSIX}.
@item ff1
@itemx ff0
@opindex ff@var{n}
-Form feed delay style. Non-@sc{posix}.
+Form feed delay style. Non-@acronym{POSIX}.
@end table
@item iexten
@opindex iexten
-Enable non-@sc{posix} special characters. May be negated.
+Enable non-@acronym{POSIX} special characters. May be negated.
@item echo
@opindex echo
@cindex case translation
Enable input and output of uppercase characters by preceding their
lowercase equivalents with @samp{\}, when @code{icanon} is set.
-Non-@sc{posix}. May be negated.
+Non-@acronym{POSIX}. May be negated.
@item tostop
@opindex tostop
@cindex background jobs, stopping at terminal write
-Stop background jobs that try to write to the terminal. Non-@sc{posix}.
+Stop background jobs that try to write to the terminal. Non-@acronym{POSIX}.
May be negated.
@item echoprt
@opindex echoprt
@opindex prterase
Echo erased characters backward, between @samp{\} and @samp{/}.
-Non-@sc{posix}. May be negated.
+Non-@acronym{POSIX}. May be negated.
@item echoctl
@itemx ctlecho
@cindex control characters, using @samp{^@var{c}}
@cindex hat notation for control characters
Echo control characters in hat notation (@samp{^@var{c}}) instead
-of literally. Non-@sc{posix}. May be negated.
+of literally. Non-@acronym{POSIX}. May be negated.
@item echoke
@itemx crtkill
@opindex crtkill
Echo the @code{kill} special character by erasing each character on
the line as indicated by the @code{echoprt} and @code{echoe} settings,
-instead of by the @code{echoctl} and @code{echok} settings. Non-@sc{posix}.
+instead of by the @code{echoctl} and @code{echok} settings. Non-@acronym{POSIX}.
May be negated.
@end table
@item decctlq
@opindex decctlq
-Same as @code{-ixany}. Non-@sc{posix}. May be negated.
+Same as @code{-ixany}. Non-@acronym{POSIX}. May be negated.
@item tabs
@opindex tabs
-Same as @code{tab0}. Non-@sc{posix}. May be negated. If negated, same
+Same as @code{tab0}. Non-@acronym{POSIX}. May be negated. If negated, same
as @code{tab3}.
@item lcase
@itemx LCASE
@opindex lcase
@opindex LCASE
-Same as @code{xcase iuclc olcuc}. Non-@sc{posix}. May be negated.
+Same as @code{xcase iuclc olcuc}. Non-@acronym{POSIX}. May be negated.
@item crt
@opindex crt
@item eol2
@opindex eol2
-Alternate character to end the line. Non-@sc{posix}.
+Alternate character to end the line. Non-@acronym{POSIX}.
@item swtch
@opindex swtch
-Switch to a different shell layer. Non-@sc{posix}.
+Switch to a different shell layer. Non-@acronym{POSIX}.
@item start
@opindex start
@item dsusp
@opindex dsusp
-Send a terminal stop signal after flushing the input. Non-@sc{posix}.
+Send a terminal stop signal after flushing the input. Non-@acronym{POSIX}.
@item rprnt
@opindex rprnt
-Redraw the current line. Non-@sc{posix}.
+Redraw the current line. Non-@acronym{POSIX}.
@item werase
@opindex werase
-Erase the last word typed. Non-@sc{posix}.
+Erase the last word typed. Non-@acronym{POSIX}.
@item lnext
@opindex lnext
Enter the next character typed literally, even if it is a special
-character. Non-@sc{posix}.
+character. Non-@acronym{POSIX}.
@end table
@item rows @var{n}
@opindex rows
-Tell the tty kernel driver that the terminal has @var{n} rows. Non-@sc{posix}.
+Tell the tty kernel driver that the terminal has @var{n} rows. Non-@acronym{POSIX}.
@item cols @var{n}
@itemx columns @var{n}
@opindex cols
@opindex columns
-Tell the kernel that the terminal has @var{n} columns. Non-@sc{posix}.
+Tell the kernel that the terminal has @var{n} columns. Non-@acronym{POSIX}.
@item size
@opindex size
terminal has. (Systems that don't support rows and columns in the kernel
typically use the environment variables @env{LINES} and @env{COLUMNS}
instead; however, GNU @command{stty} does not know anything about them.)
-Non-@sc{posix}.
+Non-@acronym{POSIX}.
@item line @var{n}
@opindex line
-Use line discipline @var{n}. Non-@sc{posix}.
+Use line discipline @var{n}. Non-@acronym{POSIX}.
@item speed
@opindex speed
If @var{timespec} is omitted with @option{--iso-8601}, the default is
@samp{auto}. On older systems, @sc{gnu} @command{date} instead
supports an obsolete option @option{-I[@var{timespec}]}, where
-@var{timespec} defaults to @samp{auto}. @sc{posix} 1003.1-2001
+@var{timespec} defaults to @samp{auto}. @acronym{POSIX} 1003.1-2001
(@pxref{Standards conformance}) does not allow @option{-I} without an
argument; use @option{--iso-8601} instead.
@cindex UTC
@cindex Greenwich Mean Time
@cindex GMT
-Use Coordinated Universal Time (@sc{utc}) by operating as if the
+Use Coordinated Universal Time (@acronym{UTC}) by operating as if the
@env{TZ} environment variable were set to the string @samp{UTC0}.
Normally, @command{date} operates in the time zone indicated by
@env{TZ}, or the system default if @env{TZ} is not set. Coordinated
Add @var{adjustment} instead of 10 to the command's priority.
On older systems, @command{nice} supports an obsolete option
-@option{-@var{adjustment}}. @sc{posix} 1003.1-2001 (@pxref{Standards
+@option{-@var{adjustment}}. @acronym{POSIX} 1003.1-2001 (@pxref{Standards
conformance}) does not allow this; use @option{-n @var{adjustment}}
instead.
@samp{SIG}. The case of the letters is ignored, except for the
@option{-@var{signal}} option which must use upper case to avoid
ambiguity with lower case option letters. The following signal names
-and numbers are supported on all @sc{posix} compliant systems:
+and numbers are supported on all @acronym{POSIX} compliant systems:
@table @samp
@item HUP
@noindent
Other supported signal names have system-dependent corresponding
-numbers. All systems conforming to @sc{posix} 1003.1-2001 also
+numbers. All systems conforming to @acronym{POSIX} 1003.1-2001 also
support the following signals:
@table @samp
@end table
@noindent
-@sc{posix} 1003.1-2001 systems that support the @sc{xsi} extension
+@acronym{POSIX} 1003.1-2001 systems that support the @sc{xsi} extension
also support the following signals:
@table @samp
@end table
@noindent
-@sc{posix} 1003.1-2001 systems that support the @sc{xrt} extension
+@acronym{POSIX} 1003.1-2001 systems that support the @sc{xrt} extension
also support at least eight real-time signals called @samp{RTMIN},
@samp{RTMIN+1}, @dots{}, @samp{RTMAX-1}, @samp{RTMAX}.
For filter programs to work together, the format of the data has to be
agreed upon. The most straightforward and easiest format to use is simply
lines of text. Unix data files are generally just streams of bytes, with
-lines delimited by the @sc{ascii} @sc{lf} (Line Feed) character,
+lines delimited by the @acronym{ASCII} @sc{lf} (Line Feed) character,
conventionally called a ``newline'' in the Unix literature. (This is
@code{'\n'} if you're a C programmer.) This is the format used by all
the traditional filtering programs. (Many earlier operating systems
The second @command{tr} command operates on the complement of the listed
characters, which are all the letters, the digits, the underscore, and
the blank. The @samp{\012} represents the newline character; it has to
-be left alone. (The @sc{ascii} tab character should also be included for
+be left alone. (The @acronym{ASCII} tab character should also be included for
good measure in a production script.)
At this point, we have data consisting of words separated by blank space.
projects / thirdparty / coreutils.git / commitdiff
