share -- make local NFS resource available for mounting by remote systems


share -F nfs [-o specific_options] [-d description] pathname [resource]


The NFS®-specific share command makes local resources available for mounting by remote systems.


The following options are available to the share command:

Specifies the File System Type (FSType). This option may be omitted if NFS is the first filesystem type listed in the /etc/dfs/fstypes file.

-o specific_options
Specify options in a comma-separated list of keywords and attribute-value-assertions for interpretation by the file-system-type-specific command.

The specific_options can be any combination of the following:

Set uid to be the effective user ID of unauthenticated users if AUTH_DES authentication is used, or to be root if AUTH_UNIX authentication is used. By default, unknown users are given the effective user ID UID_NOBODY. If uid is set to -1, access is denied.

All writes to the shared filesystem will be asynchronous. This may improve write performance on the server, but carries with it the risk of data loss on server crashes.

On a web server that supports WebNFS, serve an index file if a remote user browses a directory rather than a file. The specified index_path is appended to the pathname to form the pathname of the index file. If the index option is not used to specify an index_path, the pathname formed from pathname/index.html is used.

On a web server, the directory specified by pathname is to be shared as the publicly-accessible WebNFS directory.

Sharing will be read-only to all clients.

ro=client[:client] ...
Sharing will be read-only to the listed clients; overrides the rw suboption for the clients specified.

root=host[:host] ...
Only root users from the specified hosts will have root access. By default, no host has root access.

Sharing will be read-write to all clients.

rw=client[:client] ...
Sharing will be read-write to the listed clients; overrides the ro suboption for the clients specified.

Clients must use the AUTH_DES authentication of RPC. AUTH_UNIX authentication is the default.
If no specific_options are specified, then by default sharing will be read-write to all clients.

-d description
Provides a comment that describes the resource to be shared.

Specifies the pathname of the resource to be shared.

Specifies the name of the resource to be shared.





If no argument is specified, then share displays all of the NFS resources currently shared.

NOTE: The specific_options ro=, rw=, and root= are guaranteed to work over UDP and TCP but may not work over other transport providers.

In addition, if a resource is shared with a ro= list and a root= list, any host that is on the root= list will be given read-only access, regardless of whether that host is specified in the ro= list, unless rw is declared as the default, or the host is mentioned in a rw= list. The same is true if the resource is shared with ro as the default.

Multiple clients may be specified using the format: ``IPaddr/mask_length'' instead of naming them individually. IPaddr is an IP address, and mask_length is the number of leading 1's in a bitmask that will be applied to both IPaddr and the requesting client's IP address before comparing the resulting values. A match is obtained if the computed values are equal. For example, a client specified as ``'' includes all hosts whose IP address begins ``192.168.12'' when OR'ed with the mask ``''.

NOTE: The result of ORing IPaddr with the inverse of the specified mask must be zero. Otherwise, share will judge the address invalid. A client specified as ``'' would thus not be allowed.

share advertises its resources on applicable transports specified by the NETPATH environment variable if the variable is not set to NULL. Otherwise, share scans the /etc/netconfig file to find all appropriate transports. The recommended use of the NETPATH variable with the share command is as follows:

   # NETPATH=udp share -F nfs ...
Specifying NETPATH in this manner affects only the execution of the share command and does not affect the shell environment.

Exit codes

Successful exit

Usage error

Could not add to sharetab

Could not delete from sharetab

Could not share

Error in options parsing


The share command will fail if both ro and rw (with no qualifiers) are specified. If the same client name exists in both the ro= and rw= lists, the rw will override the ro, giving read/write access to the client specified.

Granting root access to other hosts has far reaching security implications; use the root= option with extreme caution.


Give read-only permissions to hostb:
   share -F nfs -oro=hosta,root=hostb /var
   share -F nfs -oro,root=hostb /var
Give read/write permissions to hostb:
   share -F nfs -oro=hosta,rw=hostb,root=hostb /var
   share -F nfs -oroot=hostb /var
Give read/write permissions to all hosts on network 192.168.16/24 but only allow read-only access for hosts on networks 192.168.20/24 and 192.168.25/16:
   share -F nfs -orw=,ro= /var


share(1M), unshare(1M), unshare(1Mnfs)
© 2004 The SCO Group, Inc. All rights reserved.
UnixWare 7 Release 7.1.4 - 25 April 2004