75 lines
3.0 KiB
Groff
75 lines
3.0 KiB
Groff
.\" Copyright (c) 1990 The Regents of the University of California.
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.\" All rights reserved.
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.\"
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.\" This manual is derived from one contributed to Berkeley by
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.\" Michael Rendell of Memorial University of Newfoundland.
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)tsort.1 6.3 (Berkeley) 4/23/91
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.\"
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.Dd April 23, 1991
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.Dt TSORT 1
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.Os
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.Sh NAME
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.Nm tsort
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.Nd topological sort of a directed graph
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.Sh SYNOPSIS
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.Nm tsort
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.Op Ar file
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.Sh DESCRIPTION
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.Nm Tsort
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takes a list of pairs of node names representing directed arcs in
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a graph and prints the nodes in topological order on standard output.
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Input is taken from the named
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.Ar file ,
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or from standard input if no file
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is given.
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.Pp
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Node names in the input are separated by white space and there must be an
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even number of nodes.
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.Pp
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Presence of a node in a graph can be represented by an arc from the node
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to itself.
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This is useful when a node is not connected to any other nodes.
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.Pp
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If the graph contains a cycle (and therefore cannot be properly sorted),
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one of the arcs in the cycle is ignored and the sort continues.
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Cycles are reported on standard error.
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.Sh SEE ALSO
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.Xr ar 1
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.Sh HISTORY
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A
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.Nm
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command appeared in
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.At v7 .
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This
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.Nm tsort
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command and manual page are derived from sources contributed to Berkeley by
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Michael Rendell of Memorial University of Newfoundland.
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