xref: /freebsd/share/man/man4/screen.4 (revision a79b71281cd63ad7a6cc43a6d5673a2510b51630)
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 ANSI foreground color
129		     (see table)
130		n=4X set ANSI background color
131		     (see table)
132
133		   X=0 black 	X=1 red
134		   X=2 green	X=3 brown
135		   X=4 blue	X=5 magenta
136		   X=6 cyan	X=7 light grey
137		   X=9 reset to the normal color
138
139--	E[s	Save cursor position			sc
140
141--	E[u	Restore	saved cursor position		rc
142
143--      E[x     Reset normal colors and attributes      --
144		to their default values
145
146--      E[1;nx  Set normal ANSI background color        --
147		to n (see table)
148
149--      E[2;nx  Set normal ANSI foreground color        --
150		to n (see table)
151
152--      E[3;nx  Set normal video attribute directly     --
153		to n (n	from 0 to 255)
154
155--      E[5;nx  Set normal ANSI reverse background      --
156		color to n (see	table)
157
158--      E[6;nx  Set normal ANSI reverse foreground      --
159		color to n (see	table)
160
161		   n= 0	black	   n= 8	dark grey
162		   n= 1	red	   n= 9	light red
163		   n= 2	green	   n=10	light green
164		   n= 3	brown	   n=11	yellow
165		   n= 4	blue	   n=12	light blue
166		   n= 5	magenta	   n=13	light magenta
167		   n= 6	cyan	   n=14	light cyan
168		   n= 7	light grey n=15	white
169
170--      E[7;nx  Set normal reverse video attribute      --
171		directly to n (n from 0	to 255)
172
173--	E[=p;dB	Set bell pitch (p) and duration (d),	--
174			picth is in units of 840 nS,
175			duration is units of 0,1 S.
176
177--	E[=tC	Set cursor type, 1 selects a blinking   --
178			cursor, 0 a steady cursor.
179
180--      E[=nA   Set the border color to n               --
181		(see table) (if supported by HW)
182
183--      E[=nF   Set normal foreground color to n        --
184		(see table)
185
186--      E[=nG   Set normal background color to n        --
187		(see table)
188
189--      E[=nH   Set normal reverse foreground color     --
190		to n (see table)
191
192--      E[=nI   Set normal reverse background color     --
193		to n (see table)
194
195		   n= 0	black	   n= 8	dark grey
196		   n= 1	blue	   n= 9	light blue
197		   n= 2	green	   n=10	light green
198		   n= 3	cyan	   n=11	light cyan
199		   n= 4	red	   n=12	light red
200		   n= 5	magenta	   n=13	light magenta
201		   n= 6	brown	   n=14	yellow
202		   n= 7	light grey n=15	white
203
204note: the first E in the sequences stands for ESC (0x1b)
205
206.Ed
207.Pp
208.Sh AUTHORS
209.An S�ren Schmidt Aq sos@FreeBSD.org
210