projects / unix-history / blame
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1 | .\" Copyright (c) 1990 The Regents of the University of California. |
| 2 | .\" All rights reserved. | |
| d8e69841 | 3 | .\" |
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4 | .\" This manual is derived from one contributed to Berkeley by |
| 5 | .\" Michael Rendell of Memorial University of Newfoundland. | |
| 6 | .\" | |
| 7 | .\" %sccs.include.redist.man% | |
| 8 | .\" | |
| 9 | .\" @(#)tsort.1 6.2 (Berkeley) %G% | |
| 10 | .\" | |
| 11 | .TH tsort 1 "" | |
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12 | .AT 3 |
| 13 | .SH NAME | |
| 07d825db | 14 | tsort \- topological sort of a directed graph |
| d8e69841 | 15 | .SH SYNOPSIS |
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16 | .nf |
| 17 | .ft B | |
| 18 | tsort [ file ] | |
| 19 | .ft R | |
| 20 | .fi | |
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21 | .SH DESCRIPTION |
| 22 | .I Tsort | |
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23 | takes a list of pairs of node names representing directed arcs in |
| 24 | a graph and prints the nodes in topological order on standard output. | |
| 25 | Input is taken from the named file, or from standard input if no file | |
| 26 | is given. | |
| 27 | .PP | |
| 28 | Node names in the input are separated by white space and there must be an | |
| 29 | even number of nodes. | |
| 30 | .PP | |
| 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. | |
| d8e69841 | 34 | .PP |
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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. |