# fishvfs.tcl --
#
# A "FIles transferred over SHell" virtual filesystem
# This is not an official "FISH" protocol client as described at:
#      https://wiki.tcl-lang.org/12792
# but it utilizes the same concept of turning any computer that offers
# access via ssh, rsh or similar shell into a file server.
# 
# This code requires that the template vfs (https://wiki.tcl-lang.org/11938) procedures
# have already been sourced into tclsh.
# 
# Usage: Mount ?-volume? \
#      <remote directory> \            # an existing directory on the remote filesystem
#      ?-transport <protocol>? \       # can be ssh, rsh or plink
#      ?-user <username>? \            # remote computer login name
#      ?-password <password>? \        # remote computer login password
#      ?-host <remote hostname>? \     # remote computer domain name
#      ?-port <port number>? \         # override default port
#      <virtual mount dir or URL>
# 
# examples:
# 
# Mount / -transport ssh -user root -host tcl.tk /mnt/vfs/tcl
# 
# Mount -volume /home/foo rsh://foo@localcomp
# 
# Mount -volume / -password foopass plink://[email protected]:2323/remotemount
# 
# The vfs can be mounted as a local directory, or as a URL in conjunction with 
# the "-volume" option.
# 
# The URL can be of the form:
# 
# transport://[user[:password]@]host[:port][/filename]
# 
# Option switches can be used in conjunction with a URL to specify connection 
# information; the option switch values will override the URL values.
#
# After a channel opened for writing is closed, if a file named ~/.fish_close
# exists on the remote computer it will be executed as a shell script in the 
# background (with the name of the file written as a command line argument), 
# allowing post-write processing.  For example, .fish_close could be a script
# that commits changes to a CVS repository.
# 
# client configuration:
# 
# The shell client must be in the PATH and configured for non-interactive
# (no password prompt) use.
# 
# The value of the -transport option is assumed to be the name of a handler 
# procedure which is called to handle the specifics of the particular client.
# Handlers for the supported transports (ssh, rsh, plink) already exist.
# New clients can be added simply by providing a suitable handler procedure.
# 
# server configuration:
# 
# The remote computer is assumed to have a bourne-type shell and the standard 
# GNU fileutils, but otherwise no configuration is needed.