expand.1p (6207B)
- '\" et
- .TH EXPAND "1P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual"
- .\"
- .SH PROLOG
- This manual page is part of the POSIX Programmer's Manual.
- The Linux implementation of this interface may differ (consult
- the corresponding Linux manual page for details of Linux behavior),
- or the interface may not be implemented on Linux.
- .\"
- .SH NAME
- expand
- \(em convert tabs to spaces
- .SH SYNOPSIS
- .LP
- .nf
- expand \fB[\fR-t \fItablist\fB] [\fIfile\fR...\fB]\fR
- .fi
- .SH DESCRIPTION
- The
- .IR expand
- utility shall write files or the standard input to the standard output
- with
- <tab>
- characters replaced with one or more
- <space>
- characters needed to pad to the next tab stop. Any
- <backspace>
- characters shall be copied to the output and cause the column position
- count for tab stop calculations to be decremented; the column position
- count shall not be decremented below zero.
- .SH OPTIONS
- The
- .IR expand
- utility shall conform to the Base Definitions volume of POSIX.1\(hy2017,
- .IR "Section 12.2" ", " "Utility Syntax Guidelines".
- .P
- The following option shall be supported:
- .IP "\fB\-t\ \fItablist\fR" 10
- Specify the tab stops. The application shall ensure that the argument
- .IR tablist
- consists of either a single positive decimal integer or a list of
- tabstops. If a single number is given, tabs shall be set that number of
- column positions apart instead of the default 8.
- .RS 10
- .P
- If a list of tabstops is given, the application shall ensure that it
- consists of a list of two or more positive decimal integers, separated
- by
- <blank>
- or
- <comma>
- characters, in ascending order. The
- <tab>
- characters shall be set at those specific column positions. Each tab stop
- .IR N
- shall be an integer value greater than zero, and the list is in
- strictly ascending order. This is taken to mean that, from the start of
- a line of output, tabbing to position
- .IR N
- shall cause the next character output to be in the (\c
- .IR N +1)th
- column position on that line.
- .P
- In the event of
- .IR expand
- having to process a
- <tab>
- at a position beyond the last of those specified in a multiple tab-stop
- list, the
- <tab>
- shall be replaced by a single
- <space>
- in the output.
- .RE
- .SH OPERANDS
- The following operand shall be supported:
- .IP "\fIfile\fR" 10
- The pathname of a text file to be used as input.
- .SH STDIN
- See the INPUT FILES section.
- .SH "INPUT FILES"
- Input files shall be text files.
- .SH "ENVIRONMENT VARIABLES"
- The following environment variables shall affect the execution of
- .IR expand :
- .IP "\fILANG\fP" 10
- Provide a default value for the internationalization variables that are
- unset or null. (See the Base Definitions volume of POSIX.1\(hy2017,
- .IR "Section 8.2" ", " "Internationalization Variables"
- for the precedence of internationalization variables used to determine
- the values of locale categories.)
- .IP "\fILC_ALL\fP" 10
- If set to a non-empty string value, override the values of all the
- other internationalization variables.
- .IP "\fILC_CTYPE\fP" 10
- 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), the processing of
- <tab>
- and
- <space>
- characters, and for the determination of the width in column positions
- each character would occupy on an output device.
- .IP "\fILC_MESSAGES\fP" 10
- .br
- Determine the locale that should be used to affect the format and
- contents of diagnostic messages written to standard error.
- .IP "\fINLSPATH\fP" 10
- Determine the location of message catalogs for the processing of
- .IR LC_MESSAGES .
- .SH "ASYNCHRONOUS EVENTS"
- Default.
- .SH STDOUT
- The standard output shall be equivalent to the input files with
- <tab>
- characters converted into the appropriate number of
- <space>
- characters.
- .SH STDERR
- The standard error shall be used only for diagnostic messages.
- .SH "OUTPUT FILES"
- None.
- .SH "EXTENDED DESCRIPTION"
- None.
- .SH "EXIT STATUS"
- The following exit values shall be returned:
- .IP "\00" 6
- Successful completion
- .IP >0 6
- An error occurred.
- .SH "CONSEQUENCES OF ERRORS"
- The
- .IR expand
- utility shall terminate with an error message and non-zero exit status
- upon encountering difficulties accessing one of the
- .IR file
- operands.
- .LP
- .IR "The following sections are informative."
- .SH "APPLICATION USAGE"
- None.
- .SH EXAMPLES
- None.
- .SH RATIONALE
- The
- .IR expand
- utility is useful for preprocessing text files (before sorting, looking
- at specific columns, and so on) that contain
- <tab>
- characters.
- .P
- See the Base Definitions volume of POSIX.1\(hy2017,
- .IR "Section 3.103" ", " "Column Position".
- .P
- The
- .IR tablist
- option-argument consists of integers in ascending order. Utility Syntax
- Guideline 8 mandates that
- .IR expand
- shall accept the integers (within the single argument) separated using
- either
- <comma>
- or
- <blank>
- characters.
- .P
- Earlier versions of this standard allowed the following form in
- the SYNOPSIS:
- .sp
- .RS 4
- .nf
- expand \fB[\fR-tabstop\fB][\fR-tab1,tab2,...,tabn\fB][\fIfile\fR ...\fB]\fR
- .fi
- .P
- .RE
- .P
- This form is no longer specified by POSIX.1\(hy2008 but may be present
- in some implementations.
- .SH "FUTURE DIRECTIONS"
- None.
- .SH "SEE ALSO"
- .IR "\fItabs\fR\^",
- .IR "\fIunexpand\fR\^"
- .P
- The Base Definitions volume of POSIX.1\(hy2017,
- .IR "Section 3.103" ", " "Column Position",
- .IR "Chapter 8" ", " "Environment Variables",
- .IR "Section 12.2" ", " "Utility Syntax Guidelines"
- .\"
- .SH COPYRIGHT
- Portions of this text are reprinted and reproduced in electronic form
- from IEEE Std 1003.1-2017, Standard for Information Technology
- -- Portable Operating System Interface (POSIX), The Open Group Base
- Specifications Issue 7, 2018 Edition,
- Copyright (C) 2018 by the Institute 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.opengroup.org/unix/online.html .
- .PP
- Any typographical or formatting errors that appear
- in this page are most likely
- to have been introduced during the conversion of the source files to
- man page format. To report such errors, see
- https://www.kernel.org/doc/man-pages/reporting_bugs.html .