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' $Header: /sprite/src/cmds/prefix/RCS/prefix.man,v 1.4 92/03/25 15:53:24 shirriff Exp $ SPRITE (Berkeley)
.so \*(]ltmac.sprite
.HS PREFIX cmds
.BS
.SH NAME
prefix \- Manipulate the file system prefix table
.SH SYNOPSIS
\fBprefix\fR [\fB\-p\fR [\fB\-x \fIprefix\fR]]\fR
.br
\fBprefix\fR \fB\-M \fIdevice\fR \fB[-rL] [-f] -l \fIprefix\fR
.br
\fBprefix\fR \fB\-[cdU] \fIprefix\fR
.br
\fBprefix\fR \fB\-a \fIprefix\fR [\fB\-s\fR \fIserver\fR]
.br
\fBprefix\fR \fB\-x \fIprefix\fR \fB\-[hH] \fIhost\fR
.br
\fBprefix\fR \fB\-x \fIprefix\fR \fB\-l \fIlocalName\fR
.SH "OPTIONS"
.IP "\fB\-p\fR" 14
(The default.) Print out the prefix table.
With \fB\-x\fR, print the export list of a prefix.
.IP "\fB\-x \fIprefix\fR" 14
Export a local directory given by \fB\-l\fR under the name \fIprefix\fR,
or use with \fB\-h\fR (\fB\-H\fR) to export (not export) the prefix
to a particular host.
.IP "\fB\-M \fIdevice\fR" 14
Mount the device under the local name given by the \fB\-l\fR option.
The local name is exported.
.IP "\fB\-L\fR" 14
Use with \fB\-M\fR to prevent exporting the prefix.
.IP "\fB\-r\fR" 14
Mount read-only. Use with \fB\-M\fR.
.IP "\fB\-U \fIprefix\fR" 14
Unmount the file system with the given prefix.
.IP "\fB\-f\fR" 14
Force the installation of the prefix, i.e. don't do a stat to make sure
the link exists.
.IP "\fB\-l \fIdirName\fR" 14
Specifies local name. Used with \fB\-M\fR (mount) or \fB\-x\fR (export).
.IP "\fB\-h \fIhost\fR" 14
Add \fIhost\fR to the export list associated with the prefix given
by the \fB\-x\fR option.
\fIHost\fR can either be the name of the server or its Sprite ID.
.IP "\fB\-H \fIhost\fR" 14
Remove \fIhost\fR from the export list associated with the prefix given
by the \fB\-x\fR option.
\fIHost\fR can either be the name of the server or its Sprite ID.
.IP "\fB\-a \fIprefix\fR" 14
Add \fIprefix\fR to the prefix table. If the \fB\-s\fR option is not
given a broadcast will be done to find the server.
.IP "\fB\-s \fIserver\fR" 14
Specify the server for the prefix given by the \fB\-a\fR option.
\fIServer\fR can either be the name of the server or its Sprite ID.
If \fIserver\fR is 0 a broadcast will be done to find the server.
.IP "\fB\-c \fIprefix\fR" 14
Clear the server binding for \fIprefix\fR, but retain the prefix in
the prefix table.
.IP "\fB\-d \fIprefix\fR" 14
Delete \fIprefix\fR from the prefix table altogether.
.BE
.SH DESCRIPTION
.PP
Prefix tables are cached mappings from file name prefixes to the
servers that keep files under that prefix. Under normal operation
the prefix table is updated automatically as a side-effect of
pathname lookup. The \fBprefix\fP command is used to display the file system's
prefix table,
and to manipulate its individual entries. If no options are given,
prefix prints out the contents of the prefix table (just as if the
\fB\-p\fR switch had been given). If options are given, then they
control what happens, as described above.
.SH PREFIXES AND SPRITE
.PP
The presense of a prefix is indicated by remote links in the file system.
A remote link is a circular symbolic link with a special type. They
are created via the "ln -r" command. When a server encounters a remote
link during lookup, it returns the prefix indicated by the remote link to
the client that initiated the lookup. The client loads the prefix (if it
isn't already loaded), broadcasts for the server of the prefix (if it doesn't
already know who that is), and then sends the lookup operation to the
new server. Thus the root server is bypassed after prefixes are loaded.
Prefixes can be nested arbitrarily; remote links can occur in any directory.
.PP
Servers mount local disks under a prefix that
gets exported to other Sprite hosts using the -M option. Servers
can control what hosts have access to a prefix by adding entries
to an export list using the -h option. If the export list is
empty the prefix is exported to all hosts, so adding one exportee
effectivly prevents access to all other hosts.
.SH KEYWORDS
prefix table, mount