Fix so doesn't quietly ignore un-supported options.

Things possibly to do:  

- Support for utmp uptime support

- suggested by Edward Betts <edward@hairnet.demon.co.uk>
> One of the monitors on my linux box is an old ibm monochrome display. I
> always run linux-logo as linux_logo -ascii, because the colour version
> really does not work very well. I wonder could you check the value of TERM
> and if it is linux-m, run in mono mode (print linux_logo -ascii) by default,
> as some other programs do like mc, lynx, mutt and slrn do.

  [this is possible.  Don't have time to code it right now however.. would
   want some-sort of override switch to overcome it too]


- better ascii art?

- regular ascii art for non-linux platforms.
- autoconfigure?

- better command line paramater handling.  I am lazy and don't check the
  options very well ;)

- what to do on a negative offset, is ignored right now
- a limitation for the offset would be also cool so that the penguin isn't
  destroyed if offset is to big


What follows is an e-mail chock full of stuff to add if I get a chance ;)


To: Vince Weaver <weave@eng.umd.edu>
From: Tony Nugent <T.Nugent@sct.gu.edu.au>


Vince,

G'day mate.  I'm subscribed to the linux-announce mailing list and
came across your recent announcement there of your program(s).  Always
curious, I thought I'd have a look at linux_logo.

Great little ditty, way cool!  :-)
Thanks for sharing it with us all.

Even though I have a fast P200, I don't really like working in an X
environment, much preferring to work on (at least 8) text console
screens.  I do a lot of programming - perl, shell, cgi, C, whatever.
In fact, I have a 4Mb S3 ViRGE video card, and by using some tweaked
values with SVGATextMode, I now regularly run with 8 (or more)
160-column, 75-line consoles!  It's so good to see very large chunks
of code in one go , or lynx displaying everything (or lots of things)
on web pages, or being able to view so much of a mail message in one
screen, etc - who needs "scrollback"???  -- although that still
cetainly works too!  :-)  If I had a better/larger monitor, then I'd
do it in 240x100 :-)  Some say that the font is a bit small, but it is
clear, my eyesight is excellent, and I don't find it a hassle at all.

Anyway, I was looking through the TODO in the linux_logo
distribution...

> - what to do when nonexistent params are used
>   I think ignoring is just ok

Yeah, it's an eternal problem... do you just do nothing, print the
help screen and/or an error message, or simply ignore it and do the
default?

I don't know the answer, any of these would be the RightThing(TM).
What you've done is ok, but perhaps you might want to build in some
compile-time switches/defines to create any of these behaviours.

> - what to do on a negative offset, is ignored right now

Go in from the RIGHT of the screen that many characters.  How to get
the right side of the screen??? - read on...

> - a limitation for the offset would be also cool so that the penguin isn't
>   destroyed if offset is to big
>   but this thing is IMO a bit tricky because you need the width of the display
>   and to get that width, I think, you've to use ncurses or
>   is there another possibility to get this value

Yes, there certainly is!  You get it from the console driver itself!
(No need to link with ncurses).

You say (somewhere) that you've done ascii art in the past (I've
played around with this sort of thing myself, but I'm no ascii artist
- more of a technophobe:).  And, like me, your background appears to
be DOS.  (Actually, I've been subscribed to the figlet mailing list
for several years now, and I used to visit rec.arts.ascii etc on a
fairly regular basis).  I've also played around a lot with vt100
terminals.  Check out this customised colour-enhanced termcap/terminfo
entry I have for TERM=linux...

% infocmp
#	Reconstructed via infocmp from file: /usr/share/terminfo/l/linux
linux|console|con80x25|dumb, 
	am, bce, ccc, eo, mir, msgr, xenl, xon, 
	colors#8, it#8, ncv#3, pairs#64, 
	acsc=`\004a\261f\370g\361h\260j\331k\277l\332m\300n\305o~q\304r\362s_t\303u\264v\301w\302x\263y\371z\372{\373|\374}\375~\376.\031-\030\,\021+^P0\333p\304r\304y\363z\362{\343|\330}\234, 
	bel=^G, blink=\E[5m, bold=\E[1;37;43m, civis=\E[?25l, 
	clear=\E[H\E[J, cnorm=\E[?25h\E[0;1;32;40m, cr=^M, 
	csr=\E[%i%p1%d;%p2%dr, cub=\E[%p1%dD, cub1=^H, 
	cud=\E[%p1%dB, cud1=^J, cuf=\E[%p1%dC, cuf1=\E[C, 
	cup=\E[%i%p1%d;%p2%dH, cuu=\E[%p1%dA, cuu1=\E[A, 
	cvvis=\E[?25h, dch=\E[%p1%dP, dch1=\E[P, dim=\E[2m, 
	dispc=\E[10?%\E[11m, dl=\E[%p1%dM, dl1=\E[M, 
	ech=\E[%p1%dX, ed=\E[J, el=\E[K, el1=\E[1K, enacs=\E)0, 
	flash=\E[?5h\E[?5l$<200/>, home=\E[H, hpa=\E[%i%p1%dG, 
	ht=^I, hts=\EH, ich=\E[%p1%d@, ich1=\E[@, il=\E[%p1%dL, 
	il1=\E[L, ind=^J, initc=\E]P%p1%x%p2%02x%p3%02x%p4%02x, 
	invis=\E[8m, kb2=\E[G, kbs=\177, kcbt=\E[Z, kcub1=\E[D, 
	kcud1=\E[B, kcuf1=\E[C, kcuu1=\E[A, kdch1=\E[3~, kel=\E[K, 
	kend=\E[4~, kf0=\E[21~, kf1=\E[[A, kf10=\E[21~, 
	kf11=\E[23~, kf12=\E[24~, kf13=\E[25~, kf14=\E[26~, 
	kf15=\E[28~, kf16=\E[29~, kf17=\E[31~, kf18=\E[32~, 
	kf19=\E[33~, kf2=\E[[B, kf20=\E[34~, kf3=\E[[C, kf4=\E[[D, 
	kf5=\E[[E, kf6=\E[17~, kf7=\E[18~, kf8=\E[19~, kf9=\E[20~, 
	khome=\E[1~, kich1=\E[2~, knp=\E[6~, kpp=\E[5~, kspd=^Z, 
	ll=\E[1;25r\E[25;1H, nel=^M^J, oc=\E]R, op=\E[39;49m, 
	rc=\E8, rev=\E[7m, ri=\EM, ritm=\E32m, rmacs=\E[10m, 
	rmam=\E[?7l, rmcup=\Ei, rmir=\E[4l, rmkx=, rmpch=\E[10m, 
	rmso=\E[0;1;27;32;40m, rmul=\E[24;0;1;32;40m, rs1=\Ec, 
	rs2=\E>\E[?3l\E[?4l\E[?5l\E[?7h\E[1;32;40m\E[?8h, 
	sc=\E7, setab=\E[4%p1%dm, setaf=\E[3%p1%dm, 
	setb=\E[%p1%{40}%+%dm, setf=\E[%p1%{30}%+%dm, 
	sgr=\E[0;10%?%p1%t;7%;%?%p2%t;4%;%?%p3%t;7%;%?%p4%t;5%;%?%p5%t;2%;%?%p6%t;1%;%?%p7%t;8%;%?%p9%t;11%;m, 
	sgr0=\E[0;10;1;32;40m, sitm=\E33m, smacs=\E[11m, 
	smam=\E?7h, smcup=\E[r\E[H, smir=\E[4h, smkx=, 
	smpch=\E[11m, smso=\E[0;1;33;44m, smul=\E[4;1;36m, 
	tbc=\E[3g, u6=\E[%i%d;%dR, u7=\E[6n, u8=\E[?6c, u9=\E[c, 
	vpa=\E[%i%p1%dd, 

It works really well, even if setting "norm" to produce bright green
on black sometimes has some rare but unexpected consequences.  (BTW,
it's easy to hack this entry for your own use... if you don't know
how, then get back to me and I'll explain).

I might refer you to Linux's console_codes(4) man page if you haven't
already discovered it.  There's a lot of interesting stuff in there -
there are ways to use console codes to do all sorts of interesting
things (Linux has some "extended" codes to allow you to set the
console screen saver timeout and so on).

ANSI codes are a subset of the vt-100 terminal codes, so things like
cursor positioning and so on are the same.  One of the features of
vt100-like consoles is the ability to query them for identification
and the current cursor position.  This is the clue for how to
determine the size of the current (vt) terminal!

This is how it is done:

1.	Save current cursor position:
	^[7
2.	Position the cursor in the lower right corner:
	^[[200;200H
	If the values used (here: "200;200") ARE larger than the screen,
	it will always move to the bottom-most or left-most positions.
	You might want to use larger values in case the screen is
	actually WIDER than this.
3.	Send a request for the cursor position:
	^[[6n
4.	The console will (should!) respond with:
	^[x;yR
	where x and y are the column and row co-ordinates of the
	cursor position - at the bottom-left corner.
5.	Restore the cursor to its saved position:
	^[8
6.	Parse the response string to extract the column and row values
	and VOILA! - you have the dimensions of the screen!

Armed with this information, you are now in a position to do things
like add switches that:
-	add a "clear screen" to the logo (a suggestion),
-	centers the logo on the screen, column- and/or row-wise, and
-	even rescales the logo to fit the screen!  (Tricky:)

BTW, I've never known any problems cat'ing the `%' character to a file
(as mentioned in "BUGS").  The commands:

% echo '%%% %%%' > test.file
% echo '%%% %%%' | cat > test.file

work exactly as expected.  What's the problem here?

Or perhaps I'm missing the point... you might be referring to the
presence of `%' characters in /etc/{issue.net,issue}.

Ahh yes, that would be it!

The telnetd daemon interprets `%' as an "escape" character to
represent "system variables" for display purposes (like the current
time, hostname, tty name, and so on).

Why not just add a switch that forces the `%' character to be escaped
with itself (for the purpose of sending output to this particular file)?

There's also a problem with /etc/issue.  Some `getty' programs
interpret unescaped `%' characters the same way as telnetd, while
other getty's (like `agetty', which I normally use) use `/' as the
escape character.  Again, corruption of the ascii graphic is a
potential problem.

No, a better solution is to add a switch that forces the "escape" of
certain specified characters with a specified "escape character"...

[-e c]	specify escape character for special characters.
[-c c]  specify which special character(s) to escape, eg, -c '%$&'
	escapes all three characters.  If not specified, the escape
	character will escape only itself.

That would account for any number of generic possibilities.  You might
also want to have something specific like this for the /etc/issue*
files:

[-p]    use the percent (`%') character as the escape character
        (for /etc/issue.net)
[-P]    use the forward-slash (`/') character as the escape character
        (for /etc/issue)

Oh, and now you know how you can determine in which column to start
the offset when given negative values with the -o switch!

I'll add two attachments.  One is a list of the vt102 codes, which you
might find very handy as it lists the console query codes (along with
everything else).  The other is a shell script that queries the
console in exactly the way I describe above.  (It is a response to a
question I asked in usenet a couple of years ago, and it works really
well.  I'll leave in the comments).  The script contains some escape
codes, so I hope these don't cause any hassles as text/plain.

I all hope this lot helps to inspire you to build an even more
interesting and versatile program!

Good luck.

Cheers                               .
Tony                             _--_|\
    tony@trishul.sci.gu.edu.au  /     *\ T.Nugent@sct.gu.edu.au
    ae.nugent@student.qut.edu.au\_.--._/  tnugent@cit.gu.edu.au
    tony@sctnugen.ppp.gu.edu.au       v  Brisbane Qld Australia
   -=*#*=-=*#*=-=*#*=-=*#*=-=*#*=-=*#*=-=*#*=-=*#*=-=*#*=-=*#*=-