Systems - Contains information about remote systems that
can be contacted using the uucp program.
The /usr/lib/uucp/Systems file contains an entry for each
remote system that the local system can communicate with
using uucp. The uucp program cannot establish a connection
with a remote system unless it has an entry in the Systems
file. The Systems files must be configured on each system
running the uucp program.
Note that only someone with root user authority can edit
the Systems file, which is owned by the uucp login ID.
Fields in the Systems File [Toc] [Back]
The Systems file should contain a description of each system
that the local system can establish a remote connection
with. Each line in the Systems file includes the
sys_name Time Caller Class Phone Login
The name of the remote system. In general, names should
be a maximum of seven characters in length and must be
unique. To insure compatibility with some older systems,
names should only include lowercase characters and digits.
There can be more than one entry for each sys_name.
Each additional entry for a specific system represents
an additional communications path that uucp
will sequentially try if communication cannot be
established using an earlier entry. Specifies the
times when the local system can call the remote
system. This field consists of three subfields:
day, for the day of the week (required), time, for
the time of the day when the system can call
(optional), and retry, for the minimum retry period
in minutes (optional). The day and time subfields
are not separated with spaces. The retry field is
separated by a semicolon.
The day subfield is specified using the following
keywords: system can call on any day system can
never call the remote system. The remote system
will have to call the local system. any weekday.
You can also use Mo, Tu, We, Th, Fr, and Sa, for
example MoWeFr, for Monday, Wednesday, and Friday.
The day subfield is required, unlike the time and
The time subfield is specified contains two times,
in 24-hour clock notation, which specify a range of
times. Leave this subfield blank if the remote
system can be called at any time during the day.
For example, if a remote system can only be called
during the morning, enter 0800-1200 in the
The time subfield can also specify when the remote
system cannot be reached if the time range entered
spans 0000. For example, 0800-0600 means the
remote system can be contacted at any time, except
between 6:00 am and 8:00 am.
Multiple time fields can be included by using a
comma as a separator. For example,
WK1800-0600,Sa,Su means the remote system can be
contacted at any time on a week day except between
6:00 pm. and 6:00 am, and at any time on Saturday
The optional retry subfield, specifies the minimum
time, in minutes, before uucp can try again to contact
a remote system after an unsuccessful attempt.
This subfield is separated from the rest of the
string by a semicolon. For example, Any0800-1200;3
specifies that 3 minutes is the minimum period
after which uucico can try this system again once
it has been invoked explicitly or by the cron daemon.
Usually, uucp will attempt to contact the
remote system twice and if uucp fails, it will
exit. The uucp command can be invoked again after
the 3 minute period. Specifies the type of connection
to be used to communicate with the remote system.
Use the ACU keyword for a telephone connection
using a modem or TCP (for a connection using
TCP/IP). Alternatively, sys_name can be used for a
If TCP is used, there is a subfield which specifies
a conversion protocol. The default is the g protocol.
Other protocols are e, f, and t which are
faster and more efficient than the g protocol. To
specify a particular protocol, place a comma and
the protocol letter after TCP, for example TCP,f.
The entry specified in this field must have a corresponding
entry in the /usr/lib/uucp/Devices file.
The speed in bits per second for the device.
Unless it is necessary to use a specific baud rate,
use the keyword Any. This instructs uucp to match a
speed that is appropriate for the ACU of system
connection specified in the Caller field.
For a telephone connection, the rate you enter in
this field should correspond to a rate specified in
the Class field of an entry in the
For a TCP connection, do not specify a baud rate.
Instead, use a hyphen, -, as a placeholder. The
phone number used to reach the remote system. For
a hardwired or TCP connection, use a hyphen, -, as
The phone number can be the complete phone number
of the remote system or a combination of an alphabetic
abbreviation that represents the dialing prefix
and the remainder of the number; see Dialcodes(4).
An equal sign, =, in the phone number indicates a
wait for a secondary dial tone. This may be
required when a special number sequence must be
used to access an outside line, for example. For
modems that do not have the ability to detect a
secondary dial tone, the = sign generates a pause
instead. A hyphen, -, in the phone number generates
a 1-second pause. The "chat string" which
describes the initial conversation between systems
to complete the login procedure. The string consists
of "expect-send" pairs (separated by spaces)
and optional "subexpect-subsend" pairs (separated
The "expect" portion contains characters that the
local system expects to receive from the remote
system. The "send" portion contains a string of
characters that are sent to the remote system upon
receipt of the "expect" string. For example, the
first expect string generally contains the remote
system's login prompt, and the first send string
generally contains the login ID to be used on the
remote system. The second expect string contains
the remote password prompt and the second send
string contains the remote system's password. For
in: uucp word: sysuucp
Note that the expect portion in the example contained
only the trailing part of the full strings
expected, login: and password:, respectively. The
expect string only needs to contain part of what is
expected. This helps to avoid problems with remote
systems that may use Login: or Password: instead of
login: and password:.
The use of "subexpect-subsend" strings is shown
in:--in: uucp word: sysuucp
In the example, the local system expects to receive
the string in:. If the local system gets that
string, uucp goes on to the next field in the
"expect-send" sequence, which is uucp. However, if
the local system does not get that string, it sends
its own string, which is enclosed by hyphens after
the expect string. In the above example, a null
character followed by a newline is sent. The local
system then expects the in: (the second instance of
it in the example). The newline sent to the remote
generally causes it to respond with its login
prompt, and the login ID can be sent followed by
The following strings can be included in the Login
field: Null character Backspace Suppress the newline
at the end of the send string Delay two seconds
before sending or reading more characters
Pause for approximately .25 to .50 seconds Turn on
the echo check (useful in Dialers file) Turn off
the echo check (useful in Dialers file) Send a
BREAK character Newline Carriage return Space character
Tab backslash character EOT character. Two
EOT newline characters are sent BREAK character
(same as \K) Collapse the octal digits (ddd) into a
single character before sending.
The following example is shown below as two lines
due to screen-width limitations. As a typical
example entry in Systems, it would actually be one
host1 Any ACU 1200 ch6412 "" login:--login: uucp
In this example, host1 can be called at any time
(Any) using a phone connection (ACU) at 1200 baud.
The phone number is ch (which is defined in the
Dialcodes file) followed by 6412. Initially, the
local system expects nothing (indicated by "") and
sends a sequence of four carriage returns with twosecond
delays separating them (\r\d\r\d\r\d\r).
This is typical for a remote system that must read
characters before presenting a login prompt.
Finally, the login is executed, using login ID uucp
and password sysuucp.
Contains information about available devices Contains
dial-code abbreviations Contains information about modems
used for uucp communications links
Commands: ct(1), cu(1), uutry(1), uucp(1), uucpsetup(8)
[ Back ]