plan9fox/sys/man/4/sshfs

.TH SSHFS 4
.SH NAME
sshfs - secure file transfer protocol client
.SH SYNOPSIS
.B sshfs
[
.B -abdRUGM
]
[
.B -s
.I service
]
[
.B -m
.I mtpt
]
[
.B -r
.I root
]
[
.B -u
.I uidfile
]
[
.B -g
.I gidfile
]
.IP ""
[
.B --
.I ssh-options
]
.I [user@]host
|
.B -c
.I cmdline
|
.B -p
.SH DESCRIPTION
.I Sshfs
makes the file system on a remote host accessible through the secure file transfer protocol (SFTP).
By default
.I sshfs
launches
.IR ssh (1)
to connect to
.I host
and log in as
.I user.
If
.B -c
is specified,
.I sshfs
will instead launch the command specified by
.IR cmdline
and if
.B -p
is specified,
.I sshfs
communicates with an SFTP server via stdin and stdout.
.PP
Unless
.B -M
is specified,
.I sshfs
will mount itself at the mountpoint specified by
.IR mtpt ,
or at
.B /n/ssh
if
.B -m
is not specified.
The default mount options are equivalent to calling
.I mount
(see
.IR bind (1))
with
.BR -c .
.B -a
and
.B -b
have the same function as they do with
.IR mount .
.PP
If
.B -s
is specified,
it will post itself in
.IR srv (3)
with service name
.IR service .
If the service file is mounted, the attach name (the third argument to
.IR mount (1))
can be used to specify which directory on the remote host will be mounted.
.PP
By default, relative paths are assumed relative to the user's home directory.
The
.B -r
option can be used to specify an alternative base for relative paths.
The initial mount at
.B -m
also uses this directory.
If an attach name starts with
.BR ~ ,
the user's home directory is substituted for
.BR ~ .
.PP
Since the only supported version 3 of the SFTP protocol has no way to look up numeric user and group IDs,
.I sshfs
will read the files
.B /etc/passwd
and
.B /etc/group
on the remote host to create a lookup table for them.
The location of these files can be changed with
.B -u
and
.BR -g,
whereas
.B -U
and
.B -G
will inhibit reading them entirely.
If these files cannot be accessed for any reason, numeric IDs simply remain untranslated.
.PP
Further options:
.TP
-R
Read access only.
.TP
-d
Enable debugging output.
.SH SOURCE
.B /sys/src/cmd/sshfs.c
.SH BUGS
Currently only version 3 of the SFTP protocol is supported (which is the most common version in use and the latest supported by openssh).
Unfortunately there are problems with the version 3 specification and the code relies on openssh-specific behaviour in some corner cases.
Version 4 and later also handle uid/gid translation at the server end which would remove the ugly dependence on reading remote configuration files.
.PP
Some 9P operations that should be atomic are not atomic because they do not map 1:1 to SFTP operations.
In particular there is no guarantee that a failed
.I wstat
(see
.IR stat (5))
did not change some of the fields.
.PP
The code is naive about links and assumes files with distinct names to be distinct, assigning them different QIDs.
.PP
File names with null bytes in them will confuse
.I sshfs.
.I Sshfs
should probably escape them, as well as control characters that might confuse other software.
.SH HISTORY
.I
Sshfs
first appeared in 9front (Apr, 2017).
.SH SEE ALSO
.IR ssh (1)