Revert the xterm terminal behavior to NOT clear the screen after

exiting a pager, vi, etc.

Add some example xterm*-clear entries to the termcap files to make
it easier for people to enable that behavior.

Document the examples in the man page to make them easier to find.

etc/termcap.small

@@ -312,7 +312,7 @@ xterm-basic|modern xterm common:\
 	:kD=\E[3~:kb=^H:ke=\E[?1l\E>:ks=\E[?1h\E=:le=^H:md=\E[1m:\
 	:me=\E[m:ml=\El:mr=\E[7m:mu=\Em:nd=\E[C:op=\E[39;49m:\
 	:rc=\E8:rs=\E[!p\E[?3;4l\E[4l\E>:sc=\E7:se=\E[27m:sf=^J:\
-	:so=\E[7m:sr=\EM:st=\EH:te=\E[?1049l:ti=\E[?1049h:\
+	:so=\E[7m:sr=\EM:st=\EH:\
 	:ue=\E[24m:up=\E[A:us=\E[4m:ve=\E[?12l\E[?25h:vi=\E[?25l:vs=\E[?12;25h:
 #
 # This is the only entry which you should have to customize, since "xterm"
@@ -320,3 +320,8 @@ xterm-basic|modern xterm common:\
 # color_xterm and rxvt.
 xterm|X11 terminal emulator:\
 	:tc=xterm-new:
+#
+# Add the capability to "clear the screen" after exiting vi, more/less, etc.
+xterm-clear:\
+	:te=\E[?1049l:ti=\E[?1049h:\
+	:tc=xterm-new:

share/termcap/termcap.5

@@ -53,7 +53,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd April 16, 1994
+.Dd December 13, 2009
 .Dt TERMCAP 5
 .Os
 .Sh NAME
@@ -1999,6 +1999,22 @@ Unfortunately, due to lack of a definition for string parameters in
 only
 .Xr terminfo 5
 supports these capabilities.
+.Pp
+For the
+.Xr xterm 1
+terminal emulator the traditional behavior in
+FreeBSD when exiting a pager such as
+.Xr less 1
+or
+.Xr more 1 ,
+or an editor such as
+.Xr vi 1
+is NOT to clear the screen after the program exits.
+If you prefer to clear the screen there are a number of
+.Dq xterm-clear
+entries that add this capability in the
+.Nm
+file that you can use directly, or as examples.
 .Ss Glitches and Braindamage
 Hazeltine terminals, which do not allow `~' characters to be displayed,
 should indicate
@@ -2105,6 +2121,7 @@ Hash database file containing terminal descriptions (see
 .Xr tset 1 ,
 .Xr ul 1 ,
 .Xr vi 1 ,
+.Xr xterm 1 ,
 .Xr ncurses 3 ,
 .Xr printf 3 ,
 .Xr termcap 3 ,

share/termcap/termcap.src

@@ -2800,7 +2800,12 @@ SW|screen-w|VT 100/ANSI X3.64 virtual terminal with 132 cols:\
 #
 #	I checked the limits using ncurses "captoinfo -CrTUvx", which prints
 #	the resolved length of each entry in a comment at the end - T.Dickey
+
+# Add the capability to "clear the screen" after exiting vi, more/less, etc.
 #
+xterm-clear:\
+	:te=\E[?1049l:ti=\E[?1049h:\
+	:tc=xterm-new:
 xterm-new|modern xterm:\
 	:*6=\EOF:@7=\EOF:F1=\E[23~:F2=\E[24~:K2=\EOE:Km=\E[M:\
 	:k1=\EOP:k2=\EOQ:k3=\EOR:k4=\EOS:k5=\E[15~:k6=\E[17~:\
@@ -2820,7 +2825,7 @@ xterm-basic|modern xterm common:\
 	:kD=\E[3~:kb=^H:ke=\E[?1l\E>:ks=\E[?1h\E=:le=^H:md=\E[1m:\
 	:me=\E[m:ml=\El:mr=\E[7m:mu=\Em:nd=\E[C:op=\E[39;49m:\
 	:rc=\E8:rs=\E[!p\E[?3;4l\E[4l\E>:sc=\E7:se=\E[27m:sf=^J:\
-	:so=\E[7m:sr=\EM:st=\EH:te=\E[?1049l:ti=\E[?1049h:\
+	:so=\E[7m:sr=\EM:st=\EH:\
 	:ue=\E[24m:up=\E[A:us=\E[4m:ve=\E[?12l\E[?25h:vi=\E[?25l:vs=\E[?12;25h:
 
 # The xterm-new description has all of the features, but is not completely
@@ -2886,6 +2891,12 @@ xterm-xmc|xterm alias 6:\
 #
 # An 8-bit description is doable with termcap, but there are probably no
 # termcap (or BSD curses) applications that are able to use it.
+#
+# Add the capability to "clear the screen" after exiting vi, more/less, etc.
+#
+xterm-8bit-clear:\
+	:te=\233?1049l:ti=\233?1049h:ue=\23324m:\
+	:tc=xterm-8bit:
 xterm-8bit|xterm terminal emulator 8-bit controls (X Window System):\
 	:am:km:mi:ms:xn:\
 	:co#80:it#8:li#24:\
@@ -2902,7 +2913,7 @@ xterm-8bit|xterm terminal emulator 8-bit controls (X Window System):\
 	:ke=\233?1l\E>:kh=\2331~:kl=\217D:kr=\217C:ks=\233?1h\E=:\
 	:ku=\217A:le=^H:mb=\2335m:md=\2331m:me=\233m:mr=\2337m:\
 	:nd=\233C:rc=\E8:sc=\E7:se=\23327m:sf=^J:so=\2337m:sr=\215:\
-	:st=\210:ta=^I:te=\233?1049l:ti=\233?1049h:ue=\23324m:\
+	:st=\210:ta=^I:ue=\23324m:\
 	:up=\233A:us=\2334m:vb=\233?5h\233?5l:ve=\233?25l\233?25h:\
 	:vs=\233?12;25h:vi=\233?25l:
 #
@@ -2941,6 +2952,12 @@ xterm-ic|xterm-vi|xterm with insert char:\
 	:IC=\E[%d@:ei@:ic=\E[@:im@:tc=xterm:
 #
 # Compatible with the X11R6.3 xterm
+#
+# Add the capability to "clear the screen" after exiting vi, more/less, etc.
+#
+xterm-r6-clear:\
+	:te=\E[2J\E[?47l\E8:ti=\E7\E[?47h:ue=\E[m:\
+	:tc=xterm-r6:
 xterm-r6|xterm-old|X11R6 xterm:\
 	:am:bs:km:mi:ms:pt:xn:\
 	:co#80:kn#20:li#24:\
@@ -2958,10 +2975,16 @@ xterm-r6|xterm-old|X11R6 xterm:\
 	:ke=\E[?1l\E>:kh=\E[1~:kl=\EOD:kr=\EOC:ks=\E[?1h\E=:\
 	:ku=\EOA:md=\E[1m:me=\E[m:ml=\El:mr=\E[7m:mu=\Em:nd=\E[C:\
 	:rc=\E8:rs=\E[m\E[?7h\E[4l\E>\E7\E[r\E[?1;3;4;6l\E8:\
-	:sc=\E7:se=\E[m:sf=^J:so=\E[7m:sr=\EM:te=\E[2J\E[?47l\E8:\
-	:ti=\E7\E[?47h:ue=\E[m:up=\E[A:us=\E[4m:
+	:sc=\E7:se=\E[m:sf=^J:so=\E[7m:sr=\EM:\
+	:ue=\E[m:up=\E[A:us=\E[4m:
 #
 # Compatible with the R5 xterm
+#
+# Add the capability to "clear the screen" after exiting vi, more/less, etc.
+#
+xterm-r5-clear:\
+	:te=\E[2J\E[?47l\E8:ti=\E7\E[?47h:ue=\E[m:\
+	:tc=xterm-r5:
 xterm-r5|X11R5 xterm X11R5:\
 	:am:bs:km:mi:ms:pt:xn:\
 	:co#80:kn#4:li#24:\
@@ -2974,8 +2997,8 @@ xterm-r5|X11R5 xterm X11R5:\
 	:ke=\E[?1l\E>:kh=\E[1~:kl=\EOD:kr=\EOC:ks=\E[?1h\E=:\
 	:ku=\EOA:md=\E[1m:me=\E[m:mr=\E[7m:nd=\E[C:rc=\E8:\
 	:rs=\E>\E[?1;3;4;5;6l\E[4l\E[?7h\E[m\E[r\E[2J\E[H:\
-	:sc=\E7:se=\E[m:sf=^J:so=\E[7m:sr=\EM:te=\E[2J\E[?47l\E8:\
-	:ti=\E7\E[?47h:ue=\E[m:up=\E[A:us=\E[4m:
+	:sc=\E7:se=\E[m:sf=^J:so=\E[7m:sr=\EM:\
+	:up=\E[A:us=\E[4m:
 #
 # Customization begins here.
 xterm-xfree86|xterm terminal emulator (XFree86):\