Date: Sun, 30 Aug 2020 17:37:56 +0000 (UTC) From: =?UTF-8?Q?Fernando_Apestegu=c3=ada?= <fernape@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r364976 - head/usr.bin/tsort Message-ID: <202008301737.07UHbu8A093294@repo.freebsd.org>
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Author: fernape (ports committer) Date: Sun Aug 30 17:37:56 2020 New Revision: 364976 URL: https://svnweb.freebsd.org/changeset/base/364976 Log: tsort(1): Add EXAMPLES section Add a couple of simple examples to the man page Approved by: manpages (gbe@) Differential Revision: https://reviews.freebsd.org/D25883 Modified: head/usr.bin/tsort/tsort.1 Modified: head/usr.bin/tsort/tsort.1 ============================================================================== --- head/usr.bin/tsort/tsort.1 Sun Aug 30 17:13:04 2020 (r364975) +++ head/usr.bin/tsort/tsort.1 Sun Aug 30 17:37:56 2020 (r364976) @@ -31,7 +31,7 @@ .\" @(#)tsort.1 8.3 (Berkeley) 4/1/94 .\" $FreeBSD$ .\" -.Dd December 27, 2006 +.Dd August 30, 2020 .Dt TSORT 1 .Os .Sh NAME @@ -75,6 +75,71 @@ This is primarily intended for building libraries, where optimal ordering is not critical, and cycles occur often. .El +.Sh EXAMPLES +Assuming a file named +.Pa dag +with the following contents representing a directed acyclic graph: +.Bd -literal -offset indent +A B +A F +B C +B D +D E +.Ed +.Pp +Sort the nodes of the graph: +.Bd -literal -offset indent +$ tsort dag +A +F +B +D +C +E +.Ed +.Pp +White spaces and new line characters are considered equal. +This file for example is considered equal to the one we defined before: +.Bd -literal -offset indent +$ cat dga +A B A F B C B D D E +.Ed +.Pp +Assume we add a new directed arc from D to A creating a cycle: +.Bd -literal -offset indent +A B +A F +B C +B D +D E +D A +.Ed +.Pp +Ordering the graph detects the cycle: +.Bd -literal -offset indent +$ tsort dag +tsort: cycle in data +tsort: A +tsort: B +tsort: D +D +E +A +F +B +C +.Ed +.Pp +Same as above but silencing the warning about the cycle: +.Bd -literal -offset indent +$ tsort -q dag +D +E +A +F +B +C +.Ed .Sh SEE ALSO .Xr ar 1 .Sh HISTORY
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