Date: Sun, 29 Aug 1999 16:31:58 +0200 (CEST) From: Oliver Fromme <olli@dorifer.heim3.tu-clausthal.de> To: freebsd-stable@FreeBSD.ORG Subject: Interesting ways to print 3000 spaces... Message-ID: <199908291431.QAA08474@dorifer.heim3.tu-clausthal.de>
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(was: Re: Interesting way to crash a 3.2-stable box...)
The Unicorn wrote in list.freebsd-stable:
> On Sun, Aug 29, 1999 at 01:25:22AM -0400, Tim Vanderhoek wrote:
> > On Sat, Aug 28, 1999 at 10:20:11PM -0400, Alex Perel wrote:
> > >
> > > print FOO " " x 3000;
> >
> > b$ print
> > bash: print: command not found
>
> Hehehe, in perl of course ;-)
olli@dao-lin-hay:~> perl
zsh: command not found: perl
This is probably the easiest way:
jot -n -s "" -b " " 3000
And this would be a more portable approach (jot is not
portable):
dd if=/dev/zero bs=3000 count=1 | tr '\0' " "
When using zsh, it can be done without exec'ing anything
(only using shell-builtins):
for f in {1..3000}; do echo -n " "; done
It can be done in plain /bin/sh, too, but it's a bit more
complicated... (line split for readability):
x=" "; while :; do case ${#x} in 3000) break;; esac;
x=" $x"; done; echo -n "$x"
(Note, however, that ${#x} to get the length of a string
is not portable. It _can_ be done in a portable way, but
that requires a pretty lengthy shell script, which is
available on request.)
In m4, the solution is pretty straight-forward, using
recursion (split for readability, this has to be on one
line, and be sure to get the quoting right, and don't
forget the space right befor the second-to-last closing
parens -- it's the important one!):
echo "define(iii,3000)define(\`foo',\`define(\`iii',
decr(iii))ifelse(eval(iii<1),1,,\`foo' )')foo dnl" | m4
Now this one is really interesting (or rather, sick) --
create 3000 spaces with dc:
echo "3000[[ ]P1-d0<a]salax" | dc
In all of the above solutions, you can replace the "3000"
with any other positive numeric value, to get the respective
number of spaces.
However, on my FreeBSD 2.2.8 box, the maximum value for the
m4 solution is 4043 (stack overflow at 4044), and the dc
solution coredumps for values > 95275... On a 4.0-current
box, m4 behaves exactly the same, but dc goes much further
and starts coredumping for values > 621350. (I wrote a
shell script to find out those limits, using a binary search
algorithm.)
There would be another nice solution possible, but...
printf '\t' | expand -3000
Expand refuses to use tab stops > 256. :-(
I think I'll fix that and submit a PR.
Regards
Oliver
PS: Yeah, I was bored... :-)
--
Oliver Fromme, Leibnizstr. 18/61, 38678 Clausthal, Germany
(Info: finger userinfo:olli@dorifer.heim3.tu-clausthal.de)
"In jedem Stück Kohle wartet ein Diamant auf seine Geburt"
(Terry Pratchett)
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