Random remailing script had. Help.
Thanks to Alan Barrett who sent me a script to get me started with. I have two questions still. 1) Why not just $second = rand ($#remailers+1), instead of the two line $second routine? (And why did I have to add the +1...). 2) How do I output the variables as csh environmental variables that stick around after the perl script has executed? I usually use 'setenv' but perl didn't like that. Here is Alan's script, edited a bit by me: #!/usr/bin/perl # given a set of remailers, choose two of them at random. # repeat this operation five times. # output the resulting list of 10 remailers. # # here's the list of remailers to be considered. # make it as long or as short as you like. (but no shorter than 2 entries!) # @remailers = ("One", "Two", "Three", "Four" , "Five", "Six"); # # seed the random number generator. # this is not a strong PRNG! # srand(time); foreach $cycle (1..5) { # choose random remailers $first = rand($#remailers+1); $second = rand($#remailers); $second++ if $second >= $first; # output the choices print $remailers[$first],"->",$remailers[$second],"\n"; } And a few outputs: Four->One One->Six One->Six Five->Three Four->Two One->Four One->Five Six->Four Five->Two One->Six Five->Two Two->Five Five->Three Five->Four Five->Five I may have screwed it up, as Alan originally had no +1 in the $first line, and had -1 in the next line, but it never outputed "Six" then. Background: One-Six will be addresses of Cypherpunk remailers and I am sending packages of five e-mails (~40K each) to many people a day. I figured why not appease you guys by helping with the traffic, but do it randomly and chain off two remailers per e-mail. I want csh variables though, as output. How do I get these, or how to I fetch the perl variables for a Unix command line (I am currently using 'setenv name value' then putting $name into a Unix command)? -Xenon P.S. If you wish to e-mail answers (slow!) use na38138@anon.penet.fi.
Xenon refers to the random choice script I sent him, and asks:
# choose random remailers $first = rand($#remailers+1); $second = rand($#remailers); $second++ if $second >= $first;
1) Why not just $second = rand ($#remailers+1), instead of the two line $second routine? (And why did I have to add the +1...).
If there are N remailers, then $#remailers will be N-1. (It's the value of the last index into the array, but the array starts at zero.) rand($#remailers+1) is a floating point number in the range [0,N) (including 0, but not including N). Hey, we're missing some int() operations here; it should be like this:
# choose random remailers $first = int(rand($#remailers+1)); $second = int(rand($#remailers)); $second++ if $second >= $first;
Now, $first is an integer in the range [0,N-1], which is correct for indexing into the array of available remailers. When it comes to choosing $second, we do not want to choose the same value as $first; for example, if N is 5 then we want to choose $first from the set {0,1,2,3,4}, and if we happen to choose $first=2 then we want to choose $second from the set {0,1,3,4}. The two-line calculation of $second will do that.
2) How do I output the variables as csh environmental variables that stick around after the perl script has executed? I usually use 'setenv' but perl didn't like that.
You will have to have csh parse the output of the perl script. For example, have the perl script print some csh-compatible "setenv" commands, with something like print "setenv A$cycle $remailers[$first]\n"; print "setenv B$cycle $remailers[$second]\n"; and have the csh script execute the perl script and parse its output using something like this: eval `perl perl-script` BTW, don't ever write csh scripts. See Tom Christiansen's periodic FAQ posting in comp.unix.shell.
I may have screwed it up, as Alan originally had no +1 in the $first line, and had -1 in the next line, but it never outputed "Six" then.
That was a bug, which you fixed. --apb (Alan Barrett)
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