Provided by: c3270_3.3.7p7-1build1_i386
c3270 - curses-based IBM host access tool
c3270 [options] [host]
c3270 opens a telnet connection to an IBM host in a console window. It
implements RFCs 2355 (TN3270E), 1576 (TN3270) and 1646 (LU name
selection), and supports IND$FILE file transfer. If the console is
capable of displaying colors, then c3270 emulates an IBM 3279.
Otherwise, it emulates a 3278.
The full syntax for host is:
Prepending a P: onto hostname causes the connection to go through the
telnet-passthru service rather than directly to the host. See PASSTHRU
Prepending an S: onto hostname removes the "extended data stream"
option reported to the host. See -tn below for further information.
Prepending an N: onto hostname turns off TN3270E support for the
Prepending an L: onto hostname causes c3270 to first create an SSL
tunnel to the host, and then create a TN3270 session inside the tunnel.
(This function is supported only if c3270 was built with SSL/TLS
support). Note that TLS-encrypted sessions using the TELNET START-TLS
option are negotiated with the host automatically; for these sessions
the L: prefix should not be used.
A specific Logical Unit (LU) name to use may be specified by prepending
it to the hostname with an ‘@’. Multiple LU names to try can be
separated by commas. An empty LU can be placed in the list with an
extra comma. (Note that the LU name is used for different purposes by
different kinds of hosts. For example, CICS uses the LU name as the
The hostname may optionally be placed inside square-bracket characters
‘[’ and ‘]’. This will prevent any colon ‘:’ characters in the
hostname from being interpreted as indicating option prefixes or port
numbers. This allows numeric IPv6 addresses to be used as hostnames.
On systems that support the forkpty library call, the hostname may be
replaced with -e and a command string. This will cause c3270 to
connect to a local child process, such as a shell.
The port to connect to defaults to telnet. This can be overridden with
the -port option, or by appending a port to the hostname with a colon
‘:’. (For compatability with previous versions of c3270 and with
tn3270(1), the port may also be specified as a second, separate
c3270 understands the following options:
Forces all characters to be displayed in bold. This helps with
PC consoles which display non-bold characters in unreadably dim
colors. All-bold mode is the default for color displays, but
not for monochrome displays.
Defines the dimensions and escape sequence for the alternate
(132-column) screen mode. See SCREEN SIZE SWITCHING, below.
Causes c3270 to operate in cbreak mode, instead of raw mode. In
cbreak mode, the TTY driver will properly process XOFF and XON
characters, which are required by some terminals for proper
operation. However, those characters (usually ^S and ^Q), as
well as the characters for interrupt, quit, and lnext (usually
^C, ^\ and ^V respectively) will be seen by c3270 only if
preceded by the lnext character. The susp character (usually
^Z) cannot be seen by c3270 at all.
Specifies an EBCDIC host character set. See CHARACTER SETS
Sets the initial value of toggle to false. The list of toggle
names is under TOGGLES below.
Defines the dimensions and escape sequence for the default
(80-column) screen mode. See SCREEN SIZE SWITCHING, below.
Uses file as the hosts file, which allows aliases for host names
and scripts to be executed at login. See ibm_hosts(1) for
Specifies the name of the input method to use for multi-byte
input. (Supported only when c3270 is compiled with DBCS
Specifies a keyboard map to be found in the resource
c3270.keymap.name or the file name. See KEYMAPS below for
Specifies the local encoding method for multi-byte text. name
is an encoding name recognized by the ICU library. (Supported
only when c3270 is compiled with DBCS support, and necessary
only when c3270 cannot figure it out from the locale.)
The model of 3270 display to be emulated. The model name is in
two parts, either of which may be omitted:
The first part is the base model, which is either 3278 or 3279.
3278 specifies a monochrome (green on black) 3270 display; 3279
specifies a color 3270 display.
The second part is the model number, which specifies the number
of rows and columns. Model 4 is the default.
Model Number Columns Rows
2 80 24
3 80 30
4 80 43
5 132 27
Note: Technically, there is no such 3270 display as a 3279-4 or
3279-5, but most hosts seem to work with them anyway.
The default model for a color display is 3279-4. For a
monochrome display, it is 3278-4.
-mono Prevents c3270 from using color, ignoring any color capabilities
reported by the terminal.
Makes the screen larger than the default for the chosen model
number. This option has effect only in combination with
extended data stream support (controlled by the "c3270.extended"
resource), and only if the host supports the Query Reply
structured field. The number of columns multiplied by the
number of rows must not exceed 16383 (3fff hex), the limit of
14-bit 3270 buffer addressing.
Specifies a different TCP port to connect to. n can be a name
from /etc/services like telnet, or a number. This option
changes the default port number used for all connections. (The
positional parameter affects only the initial connection.)
Causes c3270 to connect via the specified proxy, instead of
using a direct connection. The host can be an IP address or
hostname. The optional port can be a number or a service name.
For a list of supported proxy types, see PROXY below.
Causes c3270 to automatically start a pr3287 printer session.
If luname is ".", then the printer session will be associated
with the interactive terminal session (this requires that the
host support TN3270E). Otherwise, the value is used as the
explicit LU name to associate with the printer session.
Disables the interactive c3270> prompt. When used, a hostname
must be provided on the command line.
Sets the initial value of toggle to true. The list of toggle
names is under TOGGLES below.
Causes the emulator to create a Unix-domain socket when it
starts, for use by script processes to send commands to the
emulator. The socket is named /tmp/x3sck.process_id. The -p
option of x3270if causes it to use this socket, instead of pipes
specified by environment variables.
Specifies the terminal name to be transmitted over the telnet
connection. The default name is IBM-model_name-E, for example,
IBM-3279-4-E for a color display, or IBM-3278-4-E for a
Some hosts are confused by the -E suffix on the terminal name,
and will ignore the extra screen area on models 3, 4 and 5.
Prepending an s: on the hostname, or setting the
"c3270.extended" resource to "false", removes the -E from the
terminal name when connecting to such hosts.
The name can also be specified with the "c3270.termName"
-trace Turns on data stream and event tracing at startup. The default
trace file name is /tmp/x3trc.process_id.
Specifies a file to save data stream and event traces into.
Places a limit on the size of a trace file. If this option is
not specified, or is specified as 0 or none, the trace file will
be unlimited. If specified, the trace file cannot already
exist, and the (silently enforced) minimum size is 64 Kbytes.
The value of size can have a K or M suffix, indicating kilobytes
or megabytes respectively.
-xrm "c3270.resource: value"
Sets the value of the named resource to value. Resources
control less common c3270 options, and are defined under
x3270(1), s3270(1), tcl3270(1), ibm_hosts(5), x3270-script(1),
pr3287(1), telnet(1), tn3270(1)
Data Stream Programmer’s Reference, IBM GA23-0059
Character Set Reference, IBM GA27-3831
RFC 1576, TN3270 Current Practices
RFC 1646, TN3270 Extensions for LUname and Printer Selection
RFC 2355, TN3270 Enhancements
Modifications and original code Copyright 1993, 1994, 1995, 1996, 1997,
1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 by Paul Mattes.
DFT File Transfer Code Copyright October 1995 by Dick Altenbern.
RPQNAMES Code Copyright 2004, 2005 by Don Russell.
Original X11 Port Copyright 1990 by Jeff Sparkes.
Permission to use, copy, modify, and distribute this software
and its documentation for any purpose and without fee is hereby
granted, provided that the above copyright notice appear in all
copies and that both that copyright notice and this permission
notice appear in supporting documentation.
Copyright 1989 by Georgia Tech Research Corporation, Atlanta, GA 30332.
All Rights Reserved. GTRC hereby grants public use of this
software. Derivative works based on this software must
incorporate this copyright notice.
c3270 is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the file LICENSE for more
04 July 2008 c3270(1)