Annotation of src/usr.bin/cu/cu.1, Revision 1.19
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1.19 ! nicm 30: .Dd $Mdocdate: August 5 2018 $
1.1 nicm 31: .Dt CU 1
32: .Os
33: .Sh NAME
34: .Nm cu
35: .Nd serial terminal emulator
36: .Sh SYNOPSIS
37: .Nm
1.16 deraadt 38: .Op Fl dr
1.19 ! nicm 39: .Op Fl E Ar escape_char
1.1 nicm 40: .Op Fl l Ar line
1.13 bentley 41: .Op Fl s Ar speed | Fl Ar speed
1.12 nicm 42: .Nm
1.10 nicm 43: .Op Ar host
1.1 nicm 44: .Sh DESCRIPTION
45: .Nm
46: is used to connect to another system over a serial link.
47: In the era before modern networks, it was typically used to
48: connect to a modem in order to dial in to a remote host.
49: It is now frequently used for tasks such as attaching to the
50: serial console of another machine for administrative or
51: debugging purposes.
52: .Pp
53: The options are as follows:
54: .Bl -tag -width 4n
1.15 nicm 55: .It Fl d
56: Specify that the line is directly connected and
57: .Nm
58: should not allow the driver to block waiting for a carrier to be detected.
1.19 ! nicm 59: .It Fl E Ar escape_char
! 60: Specify an escape character to use instead of the default tilde.
1.1 nicm 61: .It Fl l Ar line
62: Specify the line to use.
63: Either of the forms like
1.9 nicm 64: .Pa cua00
1.1 nicm 65: or
1.9 nicm 66: .Pa /dev/cua00
1.1 nicm 67: are permitted.
68: The default is
69: .Pa /dev/cua00 .
1.9 nicm 70: See
1.1 nicm 71: .Xr cua 4
1.9 nicm 72: for information on terminal devices.
1.1 nicm 73: Users in group
74: .Dq dialer
75: are permitted to use
76: .Xr cua 4
1.9 nicm 77: devices by default.
1.17 jmc 78: .It Fl r
79: Start
80: .Nm
81: in restricted mode.
1.18 jmc 82: This prevents all local filesystem operations
83: .Po
84: .Cm ~R ,
85: .Cm ~X ,
86: and
87: .Cm ~>
88: .Pc
89: and command executions
90: .Po
91: .Cm ~C
92: and
93: .Cm ~$
94: .Pc .
1.13 bentley 95: .It Fl s Ar speed | Fl Ar speed
1.1 nicm 96: Set the speed of the connection.
97: The default is 9600.
98: .El
99: .Pp
1.10 nicm 100: If
101: .Ar host
102: is given,
103: .Nm
104: uses the
105: .Xr remote 5
1.11 nicm 106: database to retrieve the
1.15 nicm 107: .Sy dc Pq directly connected ,
1.10 nicm 108: .Sy dv Pq device
109: and
110: .Sy br Pq baud rate
111: capabilities for that host.
112: The
113: .Nm
114: utility ignores other capabilities found in that database.
115: .Pp
1.1 nicm 116: Typed characters are normally transmitted directly to the remote
117: machine (which does the echoing as well).
118: A tilde
119: .Pq Ql ~
120: appearing as the first character of a line is an escape signal; the
121: following are recognized:
122: .Bl -tag -offset indent -width Fl
123: .It Ic ~^D No or Ic ~.
124: Drop the connection and exit.
125: Only the connection is dropped \(en the login session is not terminated.
1.18 jmc 126: .It Ic ~>
1.1 nicm 127: Copy file from local to remote.
128: .Nm
129: prompts for the name of a local file to transmit.
130: .It Ic ~$
131: Pipe the output from a local
132: .Ux
133: process to the remote host.
134: The command string sent to the local
135: .Ux
136: system is processed by the shell.
137: .It Ic ~#
138: Send a
139: .Dv BREAK
140: to the remote system.
141: .It Ic ~^Z
142: Stop
143: .Nm
144: (only available with job control).
1.3 nicm 145: .It Ic ~C
146: Fork a child process on the local system to perform special protocols
147: such as XMODEM.
148: The child program will be run with the following arrangement of
149: file descriptors:
150: .Bd -literal -offset indent
1.18 jmc 151: 0 <-> remote tty in
152: 1 <-> remote tty out
153: 2 <-> local tty stderr
1.3 nicm 154: .Ed
1.7 nicm 155: .It Ic ~D
156: Deassert the data terminal ready (DTR) line briefly.
1.5 nicm 157: .It Ic ~R
158: Record all output from the remote system to a file.
159: If the given file already exists, it is appended to.
160: If no file is specified, any existing recording is stopped.
1.2 nicm 161: .It Ic ~S
162: Change the speed of the connection.
1.4 nicm 163: .It Ic ~X
1.6 nicm 164: Send a file with the XMODEM protocol.
1.1 nicm 165: .It Ic ~?
166: Get a summary of the tilde escapes.
167: .El
168: .Pp
169: When
170: .Nm
171: prompts for an argument, for example during setup of a file transfer,
172: the line typed may be edited with the standard erase and kill characters.
173: A null line in response to a prompt, or an interrupt, will abort the
174: dialogue and return the user to the remote machine.
175: .Pp
176: .Nm
177: guards against multiple users connecting to a remote system by opening
178: modems and terminal lines with exclusive access.
1.10 nicm 179: .Sh ENVIRONMENT
1.11 nicm 180: .Bl -tag -width REMOTEXXX
181: .It Ev HOST
182: The default value for
183: .Ar host
184: if none is specified via the command line.
185: .It Ev REMOTE
186: A system description, or an absolute path to a
1.10 nicm 187: .Xr remote 5
1.11 nicm 188: system description database.
189: .El
1.10 nicm 190: .Sh FILES
191: .Bl -tag -width /etc/remote
192: .It Pa /etc/remote
193: host description file
194: .El
1.11 nicm 195: .Sh EXIT STATUS
196: .Ex -std cu
197: .Sh SEE ALSO
198: .Xr remote 5
1.1 nicm 199: .Sh HISTORY
200: The
201: .Nm
202: command appeared in
203: .Bx 4.2 .
204: This version was written for
1.8 nicm 205: .Ox 5.4
1.1 nicm 206: by Nicholas Marriott.