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: [-7DEnUv] [-c cred]
[-C config] [-M master] [-p
port] [-l user]
DESCRIPTION
Console is used to manipulate console
terminals remotely or to poll running (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.
- -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
(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.
- 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 (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
- l1-9
- 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
- |
- 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
(5),
(5),
(8)