xref: /freebsd/share/man/man4/screen.4 (revision 56ca39961bd1c9946a505c41c3fc634ef63fdd42)
1.\"
2.\" $FreeBSD$
3.\"
4.Dd January 8, 1995
5.Dt SCREEN 4
6.Os FreeBSD
7.Sh NAME
8.Nm screen
9.Nd pc display interface
10.Sh DESCRIPTION
11
12Access to the
13.Ar virtual consoles
14are obtained through the device files
15ttyv0 - ttyvb in
16.Pa /dev .
17Each of these files correspond to a separate
18virtual console.
19All virtual console devices can be open at once, but only one is
20active at a time.
21The active virtual console "owns" the keyboard and
22display screen.
23.Pp
24Output to a virtual console that not currently is on the display is
25saved in a buffer that holds a "screenfull" (normally 25) lines.
26Any output written to
27.Pa /dev/console
28(the original console device) is echoed to
29.Pa /dev/ttyv0.
30.Pp
31To switch between the virtual consoles one uses the sequence
32.Ar ALT+Fn
33, which means hold down ALT and press one of the function keys.
34The
35virtual console with the same number as the function key is then
36selected as the current virtual console, and given exclusive use of
37the keyboard and display.
38This switch sequence can be changed via
39the keyboard mapping ioctl call (see keyboard.4)
40.Pp
41
42The console allows entering values that are not physically
43present on the keyboard via a special keysequence.
44To use this facility press and hold down ALT,
45then enter a decimal number from 0-255 via the numerical keypad, then
46release ALT.
47The entered value is then used as the ASCII value for one
48character.
49This way it is possible to enter any ASCII value.
50The console driver also includes a history function.
51It is activated by
52pressing the scroll-lock key.
53This holds the display, and enables the cursor
54arrows for scrolling up and down through the last scrolled out lines.
55
56The console understands a subset of the ANSI x3.64 character
57sequences.
58For compatibility with the old pccons, the PC3 character
59sequences is also supported.
60.Pp
61.Bd -literal
62ANSI	Seq	Function				Termcap entry
63======= ======= =====================================   ==============
64
65--	E7	Save cursor position			sc
66
67--	E8	Restore	saved cursor position		rc
68
69CUU     E[nA    move cursor up n lines                  up/UP (ku)
70
71CUD     E[nB    move cursor down n lines                do/DO (kd)
72
73CUF     E[nC    move cursor right n characters          nd/RI (kr)
74
75CUB     E[nD    move cursor left n characters           --/LE (kl)
76
77HPA     E[n`    move cursor to character position n     ch
78
79HPR	E[na	move cursor right n characters 		--
80
81VPA     E[nd    move cursor to line n                   cv
82
83VPR	E[ne	move cursor down n lines		--
84
85CPL     E[nF    move cursor to start of line,           -- (@7)
86		n lines up
87
88CNL     E[nE    move cursor to start of line,           nw
89		n lines down
90
91CUP	E[y;xH	Move cursor to x, y			cm
92
93HVP	E[y;xf	Move cursor to x, y			--
94
95CBT     E[nZ    Move cursor back n tab stops            bt (kB)
96
97IL      E[nL    Insert n blank lines                    al/AL
98
99ICH     E[n@    Insert n blank characters               ic/IC
100
101DL      E[nM    Delete n lines                          dl/DL
102
103DCH     E[nP    Delete n characters                     dc/DC
104
105ED	E[nJ	Erase part or all of display:		cd
106		n=0 from cursor to end of display,
107		n=1 from begin of display to cursor,
108		n=2 entire display.
109
110EL	E[nK	Erase part or all of line:		ce
111		n=0 from cursor to end of line,
112		n=1 from begin of line to cursor,
113		n=2 entire line.
114
115ECH     E[nX    Erase n characters                      ec
116
117SU      E[nS    Scroll display n lines up (forward)     sf/SF
118
119SD      E[nT    Scroll display n lines down (reverse)   sr/SR
120
121
122SGR	E[nm	Set character attributes:		--
123		n= 0 normal attribute (all off)
124		n= 1 bold (highlight)
125		n= 4 underscore (if supported by HW)
126		n= 5 blink (if supported by HW)
127		n= 7 reverse
128		n=3X set foreground color (see table)
129		n=4X set background color (see table)
130
131		   X=0 black 	X=1 red
132		   X=2 green	X=3 brown
133		   X=4 blue	X=5 magenta
134		   X=6 cyan 	X=7 white
135
136--	E[s	Save cursor position			sc
137
138--	E[u	Restore	saved cursor position		rc
139
140--	E[=p;dB	Set bell pitch (p) and duration (d),	--
141			picth is in units of 840 nS,
142			duration is units of 0,1 S.
143
144--	E[=tC	Set cursor type, 1 selects a blinking   --
145			cursor, 0 a steady cursor.
146
147--	E[=nA	Set the border color to color n
148		(see table) (if supported by HW)
149
150--	E[=nF	set normal foreground color to n 	--
151		(see table)
152
153--	E[=nG	set normal background color to n 	--
154		(see table)
155
156--	E[=nH	set reverse foreground color to n 	--
157		(see table)
158
159--	E[=nI	set reverse background color to n 	--
160		(see table)
161
162		   n= 0 black	n= 8 grey
163		   n= 1 blue	n= 9 light blue
164		   n= 2 green	n=10 light green
165		   n= 3 cyan	n=11 light cyan
166		   n= 4 red	n=12 light red
167		   n= 5 magenta n=13 light magenta
168		   n= 6 brown	n=14 yellow
169		   n= 7 white	n=15 light white
170
171note: the first E in the sequences stands for ESC (0x1b)
172
173.Ed
174.Pp
175.Sh AUTHORS
176.An S�ren Schmidt Aq sos@FreeBSD.org
177