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diff --git a/coreutils-5.3.0-bin/man/cat1p/fold.1p.txt b/coreutils-5.3.0-bin/man/cat1p/fold.1p.txt new file mode 100644 index 0000000..240affe --- /dev/null +++ b/coreutils-5.3.0-bin/man/cat1p/fold.1p.txt @@ -0,0 +1,241 @@ +fold(P) fold(P) + + + + + +NAME + fold - filter for folding lines + +SYNOPSIS + fold [-bs][-w width][file...] + +DESCRIPTION + The fold utility is a filter that shall fold lines from + its input files, breaking the lines to have a maximum of + width column positions (or bytes, if the -b option is + specified). Lines shall be broken by the insertion of a + <newline> such that each output line (referred to later + in this section as a segment) is the maximum width pos- + sible that does not exceed the specified number of col- + umn positions (or bytes). A line shall not be broken in + the middle of a character. The behavior is undefined if + width is less than the number of columns any single + character in the input would occupy. + + If the <carriage-return>s, <backspace>s, or <tab>s are + encountered in the input, and the -b option is not spec- + ified, they shall be treated specially: + + <backspace> + The current count of line width shall be decre- + mented by one, although the count never shall + become negative. The fold utility shall not + insert a <newline> immediately before or after + any <backspace>. + + <carriage-return> + + The current count of line width shall be set to + zero. The fold utility shall not insert a <new- + line> immediately before or after any <carriage- + return>. + + <tab> Each <tab> encountered shall advance the column + position pointer to the next tab stop. Tab stops + shall be at each column position n such that n + modulo 8 equals 1. + + +OPTIONS + The fold utility shall conform to the Base Definitions + volume of IEEE Std 1003.1-2001, Section 12.2, Utility + Syntax Guidelines. + + The following options shall be supported: + + -b Count width in bytes rather than column posi- + tions. + + -s If a segment of a line contains a <blank> within + the first width column positions (or bytes), + break the line after the last such <blank> meet- + ing the width constraints. If there is no <blank> + meeting the requirements, the -s option shall + have no effect for that output segment of the + input line. + + -w width + Specify the maximum line length, in column posi- + tions (or bytes if -b is specified). The results + are unspecified if width is not a positive deci- + mal number. The default value shall be 80. + + +OPERANDS + The following operand shall be supported: + + file A pathname of a text file to be folded. If no + file operands are specified, the standard input + shall be used. + + +STDIN + The standard input shall be used only if no file oper- + ands are specified. See the INPUT FILES section. + +INPUT FILES + If the -b option is specified, the input files shall be + text files except that the lines are not limited to + {LINE_MAX} bytes in length. If the -b option is not + specified, the input files shall be text files. + +ENVIRONMENT VARIABLES + The following environment variables shall affect the + execution of fold: + + LANG Provide a default value for the internationaliza- + tion variables that are unset or null. (See the + Base Definitions volume of IEEE Std 1003.1-2001, + Section 8.2, Internationalization Variables for + the precedence of internationalization variables + used to determine the values of locale cate- + gories.) + + LC_ALL If set to a non-empty string value, override the + values of all the other internationalization + variables. + + LC_CTYPE + Determine the locale for the interpretation of + sequences of bytes of text data as characters + (for example, single-byte as opposed to multi- + byte characters in arguments and input files), + and for the determination of the width in column + positions each character would occupy on a con- + stant-width font output device. + + LC_MESSAGES + Determine the locale that should be used to + affect the format and contents of diagnostic mes- + sages written to standard error. + + NLSPATH + Determine the location of message catalogs for + the processing of LC_MESSAGES . + + +ASYNCHRONOUS EVENTS + Default. + +STDOUT + The standard output shall be a file containing a + sequence of characters whose order shall be preserved + from the input files, possibly with inserted <newline>s. + +STDERR + The standard error shall be used only for diagnostic + messages. + +OUTPUT FILES + None. + +EXTENDED DESCRIPTION + None. + +EXIT STATUS + The following exit values shall be returned: + + 0 All input files were processed successfully. + + >0 An error occurred. + + +CONSEQUENCES OF ERRORS + Default. + + The following sections are informative. + +APPLICATION USAGE + The cut and fold utilities can be used to create text + files out of files with arbitrary line lengths. The cut + utility should be used when the number of lines (or + records) needs to remain constant. The fold utility + should be used when the contents of long lines need to + be kept contiguous. + + The fold utility is frequently used to send text files + to printers that truncate, rather than fold, lines wider + than the printer is able to print (usually 80 or 132 + column positions). + +EXAMPLES + An example invocation that submits a file of possibly + long lines to the printer (under the assumption that the + user knows the line width of the printer to be assigned + by lp): + + + fold -w 132 bigfile | lp + +RATIONALE + Although terminal input in canonical processing mode + requires the erase character (frequently set to + <backspace>) to erase the previous character (not byte + or column position), terminal output is not buffered and + is extremely difficult, if not impossible, to parse cor- + rectly; the interpretation depends entirely on the phys- + ical device that actually displays/prints/stores the + output. In all known internationalized implementations, + the utilities producing output for mixed column-width + output assume that a <backspace> backs up one column + position and outputs enough <backspace>s to return to + the start of the character when <backspace> is used to + provide local line motions to support underlining and + emboldening operations. Since fold without the -b option + is dealing with these same constraints, <backspace> is + always treated as backing up one column position rather + than backing up one character. + + Historical versions of the fold utility assumed 1 byte + was one character and occupied one column position when + written out. This is no longer always true. Since the + most common usage of fold is believed to be folding long + lines for output to limited-length output devices, this + capability was preserved as the default case. The -b + option was added so that applications could fold files + with arbitrary length lines into text files that could + then be processed by the standard utilities. Note that + although the width for the -b option is in bytes, a line + is never split in the middle of a character. (It is + unspecified what happens if a width is specified that is + too small to hold a single character found in the input + followed by a <newline>.) + + The tab stops are hardcoded to be every eighth column to + meet historical practice. No new method of specifying + other tab stops was invented. + +FUTURE DIRECTIONS + None. + +SEE ALSO + cut + +COPYRIGHT + Portions of this text are reprinted and reproduced in + electronic form from IEEE Std 1003.1, 2003 Edition, + Standard for Information Technology -- Portable Operat- + ing System Interface (POSIX), The Open Group Base Speci- + fications Issue 6, Copyright (C) 2001-2003 by the Insti- + tute of Electrical and Electronics Engineers, Inc and + The Open Group. In the event of any discrepancy between + this version and the original IEEE and The Open Group + Standard, the original IEEE and The Open Group Standard + is the referee document. The original Standard can be + obtained online at http://www.open- + group.org/unix/online.html . + + + +POSIX 2003 fold(P) |