xref: /freebsd/share/man/man4/screen.4 (revision c1462236787ec09d00d5e2d222edc3e34bce1e69)
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
69--	Ec	Reset					rs
70
71CUU     E[nA    move cursor up n lines                  up/UP (ku)
72
73CUD     E[nB    move cursor down n lines                do/DO (kd)
74
75CUF     E[nC    move cursor right n characters          nd/RI (kr)
76
77CUB     E[nD    move cursor left n characters           --/LE (kl)
78
79HPA     E[n`    move cursor to character position n     ch
80
81HPR	E[na	move cursor right n characters 		--
82
83VPA     E[nd    move cursor to line n                   cv
84
85VPR	E[ne	move cursor down n lines		--
86
87CPL     E[nF    move cursor to start of line,           -- (@7)
88		n lines up
89
90CNL     E[nE    move cursor to start of line,           nw
91		n lines down
92
93CUP	E[y;xH	Move cursor to x, y			cm
94
95HVP	E[y;xf	Move cursor to x, y			--
96
97CBT     E[nZ    Move cursor back n tab stops            bt (kB)
98
99IL      E[nL    Insert n blank lines                    al/AL
100
101ICH     E[n@    Insert n blank characters               ic/IC
102
103DL      E[nM    Delete n lines                          dl/DL
104
105DCH     E[nP    Delete n characters                     dc/DC
106
107ED	E[nJ	Erase part or all of display:		cd
108		n=0 from cursor to end of display,
109		n=1 from begin of display to cursor,
110		n=2 entire display.
111
112EL	E[nK	Erase part or all of line:		ce
113		n=0 from cursor to end of line,
114		n=1 from begin of line to cursor,
115		n=2 entire line.
116
117ECH     E[nX    Erase n characters                      ec
118
119SU      E[nS    Scroll display n lines up (forward)     sf/SF
120
121SD      E[nT    Scroll display n lines down (reverse)   sr/SR
122
123
124SGR	E[nm	Set character attributes:		--
125		n= 0  normal attribute (all off)
126		n= 1  bold (highlight)
127		n= 4  underscore (if supported by HW)
128		n= 5  blink (if supported by HW)
129		n= 7  reverse
130		n= 22 remove bold
131		n= 24 remove underscore
132		n= 25 remove blink
133		n= 27 remove reverse
134		n= 3X set ANSI foreground color
135		      (see table)
136		n= 4X set ANSI background color
137		      (see table)
138
139		   X=0 black 	X=1 red
140		   X=2 green	X=3 brown
141		   X=4 blue	X=5 magenta
142		   X=6 cyan	X=7 light grey
143		   X=9 reset to the normal color
144
145--	E[s	Save cursor position			sc
146
147--	E[u	Restore	saved cursor position		rc
148
149--      E[x     Reset normal colors and attributes      --
150		to their default values
151
152--      E[1;nx  Set normal ANSI background color        --
153		to n (see table)
154
155--      E[2;nx  Set normal ANSI foreground color        --
156		to n (see table)
157
158--      E[3;nx  Set normal video attribute directly     --
159		to n (n	from 0 to 255)
160
161--      E[5;nx  Set normal ANSI reverse background      --
162		color to n (see	table)
163
164--      E[6;nx  Set normal ANSI reverse foreground      --
165		color to n (see	table)
166
167		   n= 0	black	   n= 8	dark grey
168		   n= 1	red	   n= 9	light red
169		   n= 2	green	   n=10	light green
170		   n= 3	brown	   n=11	yellow
171		   n= 4	blue	   n=12	light blue
172		   n= 5	magenta	   n=13	light magenta
173		   n= 6	cyan	   n=14	light cyan
174		   n= 7	light grey n=15	white
175
176--      E[7;nx  Set normal reverse video attribute      --
177		directly to n (n from 0	to 255)
178
179--	E[=p;dB	Set bell pitch (p) and duration (d),	--
180			picth is in units of 840 nS,
181			duration is units of 0,1 S.
182
183--	E[=tC	Set cursor type, 1 selects a blinking   --
184			cursor, 0 a steady cursor.
185
186--      E[=nA   Set the border color to n               --
187		(see table) (if supported by HW)
188
189--      E[=nF   Set normal foreground color to n        --
190		(see table)
191
192--      E[=nG   Set normal background color to n        --
193		(see table)
194
195--      E[=nH   Set normal reverse foreground color     --
196		to n (see table)
197
198--      E[=nI   Set normal reverse background color     --
199		to n (see table)
200
201		   n= 0	black	   n= 8	dark grey
202		   n= 1	blue	   n= 9	light blue
203		   n= 2	green	   n=10	light green
204		   n= 3	cyan	   n=11	light cyan
205		   n= 4	red	   n=12	light red
206		   n= 5	magenta	   n=13	light magenta
207		   n= 6	brown	   n=14	yellow
208		   n= 7	light grey n=15	white
209
210note: the first E in the sequences stands for ESC (0x1b)
211
212.Ed
213.Pp
214.Sh AUTHORS
215.An S�ren Schmidt Aq sos@FreeBSD.org
216