NetBSD/sbin/rcorder/rcorder.8

.\"	$NetBSD: rcorder.8,v 1.2 2000/07/05 15:45:30 msaitoh Exp $
.\"
.\" Copyright (c) 1998
.\" 	Perry E. Metzger.  All rights reserved.
.\"
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.\"	by Perry E. Metzger.
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.Dd September 22, 1998
.Dt RCORDER 8
.Os
.Sh NAME
.Nm rcorder
.Nd print a dependency ordering of interdependent files
.Sh SYNOPSIS
.Nm
.Ar
.Sh DESCRIPTION
.Nm
is designed to print out a dependency ordering of a set of
interdependent files. Typically it is used to find an execution
sequence for a set of shell scripts in which certain files must be
executed before others.
.Pp
Each file passed to
.Nm
must be annotated with special lines (which look like comments to the
shell) which indicate the dependencies the files have upon certain
points in the sequence, known as
.Dq conditions ,
and which indicate, for each file, which
.Dq conditions
may be expected to be filled by that file.
.Pp
Within each file, a block containing a series of
.Dq REQUIRE ,
.Dq PROVIDE
and
.Dq BEFORE
lines must appear.
The format of the lines is rigid. Each line must begin with a single
.Dq # ,
followed by a single space, followed by
.Dq PROVIDE: ,
.Dq REQUIRE: 
or
.Dq BEFORE: .
No deviation is permitted.
Each dependency line is then followed by a series of conditions,
separated by whitespace. Multiple
.Dq PROVIDE ,
.Dq REQUIRE
and
.Dq BEFORE
lines may appear, but all such lines must appear in a sequence without 
any intervening lines, as once a line that does not follow the format
is reached, parsing stops.
.Pp
 An example block follows:
.Bd -literal -offset indent
# REQUIRE: networking syslog
# REQUIRE: usr
# PROVIDE: dns nscd
.Ed
.Pp
This block states that the file in which it appears depends upon the
.Dq networking ,
.Dq syslog ,
and
.Dq usr
conditions, and provides the
.Dq dns
and
.Dq nscd
conditions.
.Pp
A file may contain zero
.Dq PROVIDE
lines, in which case it provides no conditions, and may contain zero
.Dq REQUIRE
lines, in which case it has no dependencies.
There must be at least one file with no dependencies in the set of
arguments passed to
.Nm
in order for it to find a starting place in the dependency ordering.
.\" .Sh FILES
.\" .Sh EXAMPLES
.Sh DIAGNOSTICS
.Nm
may print one of the following error messages and exit with a non-zero
status if it encounters an error while processing the file list.
.Bl -diag
.It "Requirement %s has no providers, aborting."
No file has a
.Dq PROVIDE
line corresponding to a condition present in a
.Dq REQUIRE
line in another file.
.It "Circular dependency on provision %s, aborting."
A set of files has a circular dependency which was detected while
processing the stated condition.
.It "Circular dependency on file %s, aborting."
A set of files has a circular dependency which was detected while
processing the stated file.
.El
.Sh SEE ALSO
.Xr rc 8
.Sh HISTORY
The
.Nm
program first appeared in
.Nx 1.5 .
.Sh AUTHORS
Written by Perry E. Metzger (perry@piermont.com) and Matthew R.
Green (mrg@eterna.com.au).
.\" .Sh BUGS