.TH SSH 1
.SH NAME
ssh - secure shell remote login client
.SH SYNOPSIS
.B ssh 
[
.B -d
] [
.B -R
] [
.B -t
.I thumbfile
] [
.B -u
.I user
] [
.IR user @] host
[
.I cmd
.I args
.I ...
]
.SH DESCRIPTION
.I Ssh
starts a remote shell or
.I cmd
on the computer 
.I host
logged in as
.IR user .
The input file descriptor is forwarded to the
remote side and output and error descriptors
are forwarded to the local side.
.PP
The connection is authenticated and encrypted
using the SSH2 protocol. The user authenticates
itself to the host using his RSA key pair (stored
in factotum) or plaintext  passwords. To authenticate
the host to the user, the hosts RSA public key is
hashed and compared to the entries in
.B $home/lib/sshthumbs
file (see
.IR thumbprint (6)).
The 
.I thumbfile
location can be changed with the
.B -t
option.
.PP
When no
.I cmd
is specified then ssh starts a shell on the
remote side.
.PP
If the
.B $TERM
environment variable is set then a pseudo terminal
will be requested for the shell.
This can be disabled with the
.B -R
option.
.PP
If
.I keyboard-interactive
authentication fails, by default it is retried three times.
The number of tries can be changed with
.BR -T .
Setting it to zero disables keyboard-interactive authentication.
.PP
The
.B -d
option enables debug output.
.SH FILES
.TF $home/lib/sshthumbs
.TP
.B $home/lib/sshthumbs
the user's thumbfile of known host fingerprints
.SH SOURCE
.B /sys/src/cmd/ssh.c
.SH "SEE ALSO"
.IR vt (1),
.IR rsa (8),
.IR thumbprint (6),
.IR factotum (4)