xenial (1) tsort.1posix.gz

Provided by: manpages-posix_2013a-1_all bug

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.

NAME

       tsort — topological sort

SYNOPSIS

       tsort [file]

DESCRIPTION

       The  tsort  utility  shall  write  to  standard  output a totally ordered list of items consistent with a
       partial ordering of items contained in the input.

       The application shall ensure that the input consists of pairs of items (non-empty strings)  separated  by
       <blank>  characters.  Pairs  of  different  items  indicate  ordering.  Pairs of identical items indicate
       presence, but not ordering.

OPTIONS

       None.

OPERANDS

       The following operand shall be supported:

       file      A pathname of a text file to order. If no file operand is given, the standard  input  shall  be
                 used.

STDIN

       The  standard  input shall be used if no file operand is specified, and shall be used if the file operand
       is '−' and the implementation treats the '−' as meaning standard input.  Otherwise,  the  standard  input
       shall not be used.  See the INPUT FILES section.

INPUT FILES

       The input file shall be a text file.

ENVIRONMENT VARIABLES

       The following environment variables shall affect the execution of tsort:

       LANG      Provide a default value for the internationalization variables that are unset or null. (See the
                 Base Definitions volume of POSIX.1‐2008, Section 8.2, Internationalization  Variables  for  the
                 precedence   of   internationalization  variables  used  to  determine  the  values  of  locale
                 categories.)

       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).

       LC_MESSAGES
                 Determine the locale that should be used to  affect  the  format  and  contents  of  diagnostic
                 messages 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 text file consisting of the order list produced from the partially ordered
       input.

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    Successful completion.

       >0    An error occurred.

CONSEQUENCES OF ERRORS

       Default.

       The following sections are informative.

APPLICATION USAGE

       The LC_COLLATE variable need not affect the actions of tsort.  The output ordering is not  lexicographic,
       but depends on the pairs of items given as input.

EXAMPLES

       The command:

           tsort <<EOF
           a b c c d e
           g g
           f g e f
           h h
           EOF

       produces the output:

           a
           b
           c
           d
           e
           f
           g
           h

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       The Base Definitions volume of POSIX.1‐2008, Chapter 8, Environment Variables

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition,
       Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open  Group  Base
       Specifications  Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc
       and The Open Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/online.html .

       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 .