TSORT(1) General Commands Manual TSORT(1)NAME
tsort - topological sort
tsort [ file ]
Tsort produces on the standard output a totally ordered list of items consistent with a partial ordering of items mentioned in the input
file. If no file is specified, the standard input is understood.
The input consists of pairs of items (nonempty strings) separated by blanks. Pairs of different items indicate ordering. Pairs of identi-
cal items indicate presence, but not ordering.
SEE ALSO lorder(1)DIAGNOSTICS
Odd data: there is an odd number of fields in the input file.
Uses a quadratic algorithm; not worth fixing for the typical use of ordering a library archive file.
7th Edition April 29, 1985 TSORT(1)
Check Out this Related Man Page
TSORT(1P) POSIX Programmer's Manual TSORT(1P)PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond-
ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.
tsort - topological sort
The tsort utility shall write to standard output a totally ordered list of items consistent with a partial ordering of items contained in
The application shall ensure that the input consists of pairs of items (non-empty strings) separated by <blank>s. Pairs of different items
indicate ordering. Pairs of identical items indicate presence, but not ordering.
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.
The standard input shall be a text file that is used if no file operand is given.
The input file named by the file operand is a text file.
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
IEEE Std 1003.1-2001, 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.
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).
Determine the locale that should be used to affect the format and contents of diagnostic messages written to standard error.
Determine the location of message catalogs for the processing of LC_MESSAGES .
The standard output shall be a text file consisting of the order list produced from the partially ordered input.
The standard error shall be used only for diagnostic messages.
The following exit values shall be returned:
0 Successful completion.
>0 An error occurred.
CONSEQUENCES OF ERRORS
The following sections are informative.
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.
a b c c d e
f g e f
produces the output:
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 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 .
IEEE /The Open Group 2003 TSORT(1P)