[unix-history] / usr / src / usr.bin / tsort / tsort.1

.\" Copyright (c) 1990 The Regents of the University of California.
.\" All rights reserved.
.\"
.\" This manual is derived from one contributed to Berkeley by
.\" Michael Rendell of Memorial University of Newfoundland.
.\" %sccs.include.redist.roff%
.\"
.\"     @(#)tsort.1	6.3 (Berkeley) %G%
.\"
.Dd 
.Dt TSORT 1
.Os
.Sh NAME
.Nm tsort
.Nd topological sort of a directed graph
.Sh SYNOPSIS
.Nm tsort
.Op Ar file
.Sh DESCRIPTION
.Nm Tsort
takes a list of pairs of node names representing directed arcs in
a graph and prints the nodes in topological order on standard output.
Input is taken from the named
.Ar file ,
or from standard input if no file
is given.
.Pp
Node names in the input are separated by white space and there must be an
even number of nodes.
.Pp
Presence of a node in a graph can be represented by an arc from the node
to itself.
This is useful when a node is not connected to any other nodes.
.Pp
If the graph contains a cycle (and therefore cannot be properly sorted),
one of the arcs in the cycle is ignored and the sort continues.
Cycles are reported on standard error.
.Sh SEE ALSO
.Xr ar 1
.Sh HISTORY
A
.Nm
command appeared in
.At v7 .
This
.Nm tsort
command and manual page are derived from sources contributed to Berkeley by
Michael Rendell of Memorial University of Newfoundland.
Commit	Line	Data
07d825db KB	1	.\" Copyright (c) 1990 The Regents of the University of California.
07d825db KB	2	.\" All rights reserved.
d8e69841	3	.\"
07d825db KB	4	.\" This manual is derived from one contributed to Berkeley by
07d825db KB	5	.\" Michael Rendell of Memorial University of Newfoundland.
8f5f4c1c	6	.\" %sccs.include.redist.roff%
07d825db	7	.\"
8f5f4c1c	8	.\" @(#)tsort.1 6.3 (Berkeley) %G%
07d825db	9	.\"
8f5f4c1c CL	10	.Dd
	11	.Dt TSORT 1
	12	.Os
	13	.Sh NAME
	14	.Nm tsort
	15	.Nd topological sort of a directed graph
	16	.Sh SYNOPSIS
	17	.Nm tsort
	18	.Op Ar file
	19	.Sh DESCRIPTION
	20	.Nm Tsort
07d825db KB	21	takes a list of pairs of node names representing directed arcs in
07d825db KB	22	a graph and prints the nodes in topological order on standard output.
8f5f4c1c CL	23	Input is taken from the named
	24	.Ar file ,
	25	or from standard input if no file
07d825db	26	is given.
8f5f4c1c	27	.Pp
07d825db KB	28	Node names in the input are separated by white space and there must be an
07d825db KB	29	even number of nodes.
8f5f4c1c	30	.Pp
07d825db KB	31	Presence of a node in a graph can be represented by an arc from the node
	32	to itself.
	33	This is useful when a node is not connected to any other nodes.
8f5f4c1c	34	.Pp
07d825db KB	35	If the graph contains a cycle (and therefore cannot be properly sorted),
	36	one of the arcs in the cycle is ignored and the sort continues.
	37	Cycles are reported on standard error.
8f5f4c1c CL	38	.Sh SEE ALSO
	39	.Xr ar 1
	40	.Sh HISTORY
	41	A
	42	.Nm
	43	command appeared in
	44	.At v7 .
	45	This
	46	.Nm tsort
	47	command and manual page are derived from sources contributed to Berkeley by
	48	Michael Rendell of Memorial University of Newfoundland.