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Clarify NUL vs null byte vs null character.

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Paul Eggert
2005-03-26 18:43:30 +00:00
parent 5bb064a261
commit f01ef502f2
2 changed files with 13 additions and 9 deletions
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doc/ChangeLog
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@@ -1,3 +1,7 @@
2005-03-26 Paul Eggert <eggert@cs.ucla.edu>
* coreutils.texi: Clarify NUL vs null byte vs null character.
2005-03-18 Paul Eggert <eggert@cs.ucla.edu>
* coreutils.texi (nohup invocation): Clarify nohup.out creation.

18
doc/coreutils.texi
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@@ -3433,7 +3433,7 @@ However, fields that extend to the end of the line,
as @option{-k 2}, or fields consisting of a range, as @option{-k 2,3},
retain the field separators present between the endpoints of the range.
To specify a zero byte (@acronym{ASCII} @sc{nul} (Null) character) as
To specify a null character (@acronym{ASCII} @sc{nul}) as
the field separator, use the two-character string @samp{\0}, e.g.,
@samp{sort -t '\0'}.
@@ -3473,9 +3473,9 @@ uniq} inspects the entire line. @xref{uniq invocation}.
@opindex -z
@opindex --zero-terminated
@cindex sort zero-terminated lines
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).
Treat the input as a set of lines, each terminated by a null character
(@acronym{ASCII} @sc{nul}) instead of a line feed
(@acronym{ASCII} @sc{lf}).
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 file names (even those containing blanks
@@ -4416,7 +4416,7 @@ disabled, width of references is not taken into account in the output
line width computations.
@item
All 256 characters, even @sc{nul}s, are always read and processed from
All 256 bytes, even null bytes, are always read and processed from
input file with no adverse effect, even if @sc{gnu} extensions are disabled.
However, System V @command{ptx} does not accept 8-bit characters, a few
control characters are rejected, and the tilde @kbd{~} is also rejected.
@@ -8890,14 +8890,14 @@ are often symbolic links.
@opindex --files0-from=@var{FILE}
@cindex including files from @command{du}
Rather than processing files named on the command line, process those
in the @sc{nul}-terminated list in file @var{FILE}.
named in file @var{FILE}; each name is terminated by a null byte.
This is useful with the @option{--total} (@option{-c}) option when
the list of file names is so long that it may exceed a command line
length limitation.
In such cases, running @command{du} via @command{xargs} is undesirable
because it splits the list into pieces and makes @command{du} print a
total for each sublist rather than for the entire list.
One way to produce a list of @sc{nul}-terminated file names is with @sc{gnu}
One way to produce a list of null-byte-terminated file names is with @sc{gnu}
@command{find}, using its @option{-print0} predicate.
Do not specify any @var{FILE} on the command line when using this option.
@@ -8953,8 +8953,8 @@ is at level 0, so @code{du --max-depth=0} is equivalent to @code{du -s}.
@opindex -0
@itemx --null
@opindex --null
@cindex output @sc{nul}-terminated lines
Output the zero byte (@sc{nul}) at the end of each line, rather than a newline.
@cindex output null-byte-terminated lines
Output a null byte at the end of each line, rather than a newline.
This option enables other programs to parse the output of @command{du}
even when that output would contain file names with embedded newlines.