Provided by: conserver-client_8.2.7-3_amd64 
NAME
console - console server client program
SYNOPSIS
console [generic-args] [-aAfFsS] [-e esc] console
console [generic-args] [-iIuwWx] [console]
console [generic-args] [-hPqQrRV] [-[bB] message] [-d [user][@console]] [-t [user][@console] message]
[-[zZ] cmd]
generic-args: [-7DEknUv] [-c cred] [-C config] [-M master] [-p port] [-l user]
DESCRIPTION
Console is used to manipulate console terminals remotely or to poll running conserver(8) daemons for
status information.
In the first form above, console asks the user's password before granting interactive access to a console
(on a non-trusted system), since such a session may provide single-user access. If the server's
autocompletion feature is enabled, only as much of the console name as is required to identify it
uniquely to the server is required.
For non-interactive options, console outputs only the requested information and exits.
Console knows only of a primary conserver host (see the -M option below), to which it initially connects.
In a multi-server environment, the primary server may refer the client to a different server handling the
requested console, or it will provide a list of all servers if required (as when console is invoked with
the -r option). Console then opens connections to the appropriate server(s). It is not necessary for
the user of console to know which server manages which consoles, as long as console knows a valid primary
server and all available consoles are listed in the primary server's configuration file.
OPTIONS
Options may be given as separate arguments (e.g., -v -w) or clustered (e.g., -vw). Options and their
arguments may be separated by optional white space. Option arguments containing spaces or other
characters special to the shell must be quoted.
-7 Strip the high bit off of all data received, whether from user input or from the server,
before any processing occurs. Disallows escape sequence characters with the high bit set.
-a Access a console with a two-way (read-write) connection (this is the default). The connection
is dropped to spy mode if someone else is attached read-write.
-bmessage Broadcast a message to all users connected to each server.
-Bmessage Same as -b but just send a message to users on the primary server.
-ccred Load an SSL certificate and key from the PEM encoded file cred.
-Cconfig Use the per-user configuration file config.
-d Disconnect the users specified by user@console. You may specify the target as user
(disconnect the user, regardless of what console they are attached to), @console (disconnect
all users attached to console), or user@console (disconnect the user attached to console).
-D Enable debugging output.
-eesc Set the initial two-character escape sequence to those represented by esc. Any of the forms
output by cat(1)'s -v option are accepted. The default value is ``^Ec''.
-E If encryption has been built into the code (--with-openssl), encrypted client connections are,
by default, a requirement. This option disables any attempt at creating an encrypted
connection. If you'd like to use encrypted connections when your server supports it, but
fallback to non-encrypted otherwise, the -U option is what you want.
-f Same as -a except it will force any existing connection into spy mode.
-h Display a brief help message.
-i Display status information in a machine-parseable format (see below for the details).
-I Same as -i but just acts on the primary server.
-k Abort the connection if the console is not in the `up' state immediately upon connecting.
-luser Set the login name used for authentication to user. By default, console uses $USER if its uid
matches the user's real uid, or $LOGNAME if its uid matches the user's real uid, or else the
name associated with the user's real uid.
-Mmaster The console client program polls master as the primary server, rather than the default set at
compile time (typically ``console''). The default master may be changed at compile time using
the --with-master option. If --with-uds is used to enable Unix domain sockets, however, this
option points console to the directory which holds those sockets. The default master
directory (``/tmp/conserver'') may be changed at compile time using the --with-uds option.
-n Do not read the system-wide configuration file.
-pport Set the port to connect to. This may be either a port number or a service name. The default
port may be changed at compile time using the --with-port option. If the --with-uds option
was used, this option is ignored.
-P Display the pid of the master daemon process on each server.
-q The console client connects to each server to request that the server daemon quit (shut down).
The root password of the host(s) running conserver is required unless the local host is listed
as ``trusted'' in the conserver.cf file; in that case, just press <return>.
-Q Same as -q but just acts on the primary server.
-r Display daemon versions. The console client connects to each server to request its version
information.
-R Same as -r but just acts on the primary server.
-s Request a read-only (spy mode) connection. In this mode all the escape sequences (below)
work, or report errors, but all other keyboard input is discarded.
-t Send a text message to user@console. You may specify the target as user (send to user,
regardless of what console they are attached to), @console (send to all users attached to
console), or user@console (send to user attached to console).
-u Show a list of all consoles with status (`up', `down', or `init') and attached users
(user@host if attached read-write, `<spies>' if only users in spy mode, or `<none>').
-U If encryption has been built into the code (--with-openssl), encrypted client connections are,
by default, a requirement. This option allows the client to attempt an encrypted connection
but fall back to a non-encrypted connection if the server doesn't support encryption. If the
encryption handshake is failing, disabling encryption on the client with the -E option is
probably what you want.
-v Be more verbose when building the connection(s). Use this option in combination with any of
`show' options (below) for added benefit.
-V Output the version and settings of the console client program and then exit.
-w Show a list of all who are currently connected to consoles, including the hostnames where the
console connections originate and the idle times. This is useful to see if anybody is
actively using the console system if it becomes necessary to shut down conserver.
-W Same as -w but just acts on the primary server.
-x Show a list of consoles and devices.
-zcmd Sends a command (cmd) to each server and displays the result. The valid commands are:
bringup Try to connect all consoles marked as down (this is equivalent to sending the
server a SIGUSR1)
SIGUSR1 Same as bringup
help Displays the help message
pid Returns the pid of the server (this is equivalent to -P)
quit Instructs the server to shut down (this is equivalent to -q or sending the server
a SIGTERM)
SIGTERM Same as quit
reconfig Instructs the server to reload the configuration file, then perform the actions of
reopen (this is equivalent to sending the server a SIGHUP)
SIGHUP Same as reconfig
reopen Instructs the server to reopen all logfiles, then perform the actions of bringup
(this is equivalent to sending the server a SIGUSR2)
SIGUSR2 Same as reopen
version Returns the version of the server (this is equivalent to -V)
-Zcmd Same as -z but just sends cmd to the primary server.
The -A, -F, or -S options have the same effect as their lower-case variants. In addition, they each
request the last 20 lines of the console output after making the connection (as if ``^Ecr'' were typed).
The -i, -u, -w, and -x options can be given a console name, which will limit their output to that
console.
The -i option outputs status information regarding each console in 15 colon-separated fields.
name The name of the console.
hostname,pid,socket
The hostname, pid, and socket number of the child process managing the console.
type The type of console. Values will be a `/' for a local device, `|' for a command, `!' for a remote
port, `%' for a Unix domain socket, and `#' for a noop console.
console-details
The details regarding the console. The values here (all comma-separated) depend on the type of
the console. Local devices will have values of the device file, baud rate/parity, and file
descriptor for the device. Commands will have values of the command, the command's pid, the
pseudo-tty, and file descriptor for the pseudo-tty. Remote ports will have values of the remote
hostname, remote port number, ``raw'' or ``telnet'' protocol, and file descriptor for the socket
connection. Unix domain sockets will have the path to the socket and the file descriptor for the
socket connection. Noop consoles will have nothing.
users-list
The details of each user connected to the console. The details for each user are an `@' separated
list of `w', `r', or `s' (for read-write, read-only, or suspended), username, hostname the user is
on, the user's idle time, and (for `r' and `s' users only) ``rw'' or ``ro'' (if the user wants
read-write mode or not). Each user bundle is separated by commas.
state The state of the console. Values with either be ``up'', ``down'', or ``init''.
perm This value will either be ``rw'' or ``ro''. It will only be ``ro'' if the console is a local
device (`/' type) and the permissions are such that the server can open the file for read, but not
write.
logfile-details
The details regarding the logging for the console. The comma-separated values will be the
logfile, ``log'' or ``nolog'' (if logging is on or not - toggled via ``^EcL''), ``act'' or
``noact'' (if activity logging is enabled or not - the `a' timestamp option), the timestamp
interval, and the file descriptor of the logfile.
break The default break sequence used for the console.
reup If the console is currently down and the automatic reconnection code is at work, it will have the
value of ``autoup'', otherwise it will be ``noautoup''.
aliases
The console aliases are presented in a comma-separated list.
options
The active options for the console are presented in a comma-separated list.
initcmd
The initcmd configuration option for the console.
idletimeout
The idletimeout configuration option for the console.
idlestring
The idlestring configuration option for the console.
CONFIGURATION
Console reads configuration information from the system-wide configuration file (console.cf), then the
per-user configuration file (.consolerc), and then applies command-line arguments. Each configuration
location can override the previous. The same happens when parsing an individual file - the later entries
always override the earlier entries. Because of that, you should put ``global'' defaults first and more
specific defaults second.
The configuration file is read using the same parser as conserver.cf(5), and you should check that
manpage for parser details. Console recognizes the following configuration blocks.
config hostname|ipaddr
Define a configuration block for the client host named hostname or using the address ipaddr. If
the value of ``*'' is used, the configuration block will be applied to all client hosts.
escape esc
Set the escape sequence (see the -e command-line flag).
master master
Set the default master to master (see the -M command-line flag).
playback num|""
Override the playback length for the p escape command to num lines (if the server supports
it). Using the special value of ``0'' will cause the client to use the number of lines of
the current terminal (if that can be determined). If the null string (``""'') is used, the
playback length will not be overridden.
port port
Set the default port to port (see the -p command-line flag).
replay num|""
Override the replay length for the r escape command to num lines (if the server supports
it). Using the special value of ``0'' will cause the client to use the number of lines of
the current terminal (if that can be determined). If the null string (``""'') is used, the
replay length will not be overridden.
sslcacertificatefile filename
Load the valid CA certificates for the SSL connection from the PEM encoded file.
sslcacertificatepath directory
Load the valid CA certificates for the SSL connection from the PEM encoded files in the
directory.
sslcredentials filename
Set the SSL credentials file location (see the -c command-line flag).
sslenabled yes|true|on|no|false|off
Set whether or not encryption is attempted when talking to servers (see the -E command-line
flag).
sslrequired yes|true|on|no|false|off
Set whether or not encryption is required when talking to servers (see the -U command-line
flag).
striphigh yes|true|on|no|false|off
Set whether or not to strip the high bit off all data received (see the -7 command-line
flag).
username user
Set the username passed to the server to user (see the -l command-line flag).
terminal type
Define a configuration block when using a terminal of type type. If the value of ``*'' is used,
the configuration block will be applied to all terminal types.
attach string|""
Set a string to print when successfully attached to a console. Character substitions will
be performed based on the attachsubst value and occur before interpretation of the special
characters below. If the null string (``""'') is used, no string will be printed. string
is a simple character string with the exception of `\' and `^':
\a alert
\b backspace
\f form-feed
\n newline
\r carriage-return
\t tab
\v vertical-tab
\\ backslash
\^ circumflex
\ooo octal representation of a character (where ooo is one to three octal digits)
\c character c
^? delete
^c control character (c is ``and''ed with 0x1f)
An interesting use of attach and attachsubst would be:
terminal xterm {
attach "^[]0;conserver: U@C^G";
attachsubst U=us,C=cs;
}
attachsubst c=t[n]f[,...]|""
Perform character substitutions on the attach value. A series of replacements can be
defined by specifying a comma-separated list of c=t[n]f sequences where c is any printable
character, t specifies the replacement value, n is a field length (optional), and f is the
format string. t can be one of the characters below, catagorized as a string replacement
or a numeric replacement, which dictates the use of the n and f fields.
String Replacement
u username
c console name
Numeric Replacement
none available (yet)
For string replacements, if the replacement isn't at least n characters, it will be padded
with space characters on the left. f must be `s'. For numeric replacements, the value
will be formatted to at least n characters, padded with 0s if n begins with a 0, and space
characters otherwise. f must be either `d', `x' or `X', specifying a decimal, lower-case
hexadecimal, or an uppercase hexadecimal conversion. If the null string (``""'') is used,
no replacements will be done.
detach string|""
Set a string to print once detached from a console. Character substitions will be
performed based on the detachsubst value. See the attach option for an explanation of
string. If the null string (``""'') is used, no string will be printed.
detachsubst c=t[n]f[,...]|""
Perform character substitutions on the detach value. See the attachsubst option for an
explanation of the format string.
A simple configuration to set a new default escape sequence and override the master location would be:
# override options for all hosts
config * {
master localhost;
escape ^Ee;
}
# set things more specific to host1
# note: if the entries were reversed, host1
# would also use localhost.
config host1 {
master console1;
}
ESCAPE SEQUENCES
The connection can be controlled by a two-character escape sequence, followed by a command. The default
escape sequence is ``control-E c'' (octal 005 143). (The escape sequences are actually processed by the
server; see the conserver(8) man page for more information.) Commands are:
. disconnect
; move to another console
a attach read-write if nobody already is
b send broadcast message to all users on this console
c toggle flow control (don't do this)
d down the current console
ecc change the escape sequence to the next two characters
f forcibly attach read-write
g group info
i information dump
L toggle logging on/off
l? list the break sequences available
l0 send the break sequence associated with this console
l1-9a-z send the specific break sequence
m display the "message of the day"
o close (if open) and reopen the line (to clear errors (silo overflows)) and the log file
p playback the last 60 lines of output
P set number of playback lines
r replay the last 20 lines of output
R set number of replay lines
s switch to spy mode (read only)
u show status of hosts/users in this group
v show the version of the group server
w who is using this console
x examine this group's devices and modes
z suspend this connection
! invoke task
| attach a local command to the console
? display list of commands
^M (return) continue, ignore the escape sequence
^R (ctrl-R) replay the last line only
\ooo send character having octal code ooo (must specify three octal digits)
If any other character is hit after the escape sequence, all three characters will be discarded. Note
that a line break or a down command can only be sent from a read-write connection. To send the escape
sequence through the connection one must redefine the outer escape sequence, or use ^Ec\ooo to send the
first escape character before typing the second character directly.
In the -u output, the login ``<none>'' indicates no one is viewing that console, and the login
``<spies>'' indicates that no one has a read-write connection (only read-only).
When running a local command via ``^Ec|'', you can type `^C' to send the command a SIGHUP, `^\' to send
the command a SIGKILL, and `o' to toggle the display of the console data.
EXAMPLES
console -u Outputs something like:
dumb up <none>
expert up ksb@mentor
tyro up <spies>
mentor up <none>
sage up fine@cis
The <none> indicates no one is viewing dumb or mentor, the <spies> indicates only read-
only connections exist for tyro, and other login@host entries indicate users attached
read-write to sage and expert.
console -w Outputs something like:
ksb@extra attach 2days expert
file@cis attach 21:46 sage
dmr@alice spy 0:04 tyro
The third column is the idle time of the user. Either hours:minutes or number of days is
displayed.
console -e "^[1" lv426
Requests a connection to the host ``lv426'' with the escape characters set to ``escape
one''.
FILES
The following default file locations may be overridden at compile time or by the command-line options
described above. Run console -V to see the defaults set at compile time.
/etc/console.cf system-wide configuration file
$HOME/.consolerc per-user configuration file
BUGS
It is possible to create a loop of console connections, with ugly results. Never run console from within
a console connection (unless you set each escape sequence differently).
The -i output can produce more than the stated number of fields of information if the user-provided
information has embedded colons.
I'm sure there are more, I just don't know where they are. Please let me know if you find any.
AUTHORS
Thomas A. Fine, Ohio State Computer Science
Kevin Braunsdorf, Purdue University Computing Center
Bryan Stansell, conserver.com
SEE ALSO
conserver.cf(5), conserver.passwd(5), conserver(8)
conserver-8.2.7 2022/07/07 CONSOLE(1)