Hi,
I am having trouble with generating random numbers. can this be done with awk?
So I have a file that looks like this:
23 30
24 40
26 34
So column1 is start and column2 is end. I want to generate 3 random #'s between start and stop:
So the output will look like this:
... (9 Replies)
Im new to C, and Im having a hard time getting a random number.
In bash, I would do something similar to the following to get a random number;
#!/bin/bash
seed1=$RANDOM
seed2=$RANDOM
seed3=$RANDOM
SEED=`expr $seed1 * $seed2 / $seed3`
echo ${SEED%.*}
Now, in online examples... (4 Replies)
Hi All,
I have extracted some report from database for few activities done.
Now I have a requirement to add some random time(In range of 10-35) in front of each activity.
Can be generated random numbers in any bash/sh shell within a given number range, let's say in between 10-30.
... (10 Replies)
Hello All, I am stuck up in a program where the rand functions ends up giving all the same integers. Tried sleep, but the numbers turned out to be same... Can anyone help me out how to fix this issue ? I have called the srand once in the program, but I feel like when I call fork the child process... (5 Replies)
Hi,
Do anybody knows how to use awk or any command to random print out 1000 number which start from range 1 to 150000?
I know that "rand" in awk can do similar random selection.
But I have no idea how to write a code that can random pick 1000 number from range 1 to 150000 :confused:
... (1 Reply)
Hi there I am trying to generate a random number between 40 and 70 using the shell here is my code so far and it keeps going above 70. all help much appreciated!
comp=$(( RANDOM%70+40 ))
echo $comp (4 Replies)
Having a hard time with this. Very new to scripting and linux. Spent all sunday trying to do this. Appreciate some help and maybe help breaking down what the syntax does.
Create a Bash program. It should have the following properties
• Creates a secret number between 1 and 100
i. The... (3 Replies)
Hi,
How can I generate a string of random characters (alpha+numeric) of a particular length ?
For e.g. for
n=5, output = 'kasjf'
n=10, output = 'hedbcd902k'
Also, please let me know if random (valid) dates could also be generated.
Thanks (7 Replies)
Hi Guys and gals...
As you know I am getting to grips with POSIX and hit this stumbling block.
Generating two random numbers 0 to 255 POSIXly. Speed in not important hence the 'sleep 1' command.
I have done a demo that works, but it sure is ugly! Is there a better way?
#!/bin/sh
# Random... (12 Replies)
Discussion started by: wisecracker
12 Replies
LEARN ABOUT DEBIAN
arc4random
RANDOM(9) BSD Kernel Developer's Manual RANDOM(9)NAME
arc4rand, arc4random, random, read_random, srandom -- supply pseudo-random numbers
SYNOPSIS
#include <sys/libkern.h>
void
srandom(u_long seed);
u_long
random(void);
void
arc4rand(void *ptr, u_int length, int reseed);
u_int32_t
arc4random(void);
#include <sys/random.h>
int
read_random(void *buffer, int count);
DESCRIPTION
The random() function will by default produce a sequence of numbers that can be duplicated by calling srandom() with '1' as the seed. The
srandom() function may be called with any arbitrary seed value to get slightly more unpredictable numbers. It is important to remember that
the random() function is entirely predictable, and is therefore not of use where knowledge of the sequence of numbers may be of benefit to an
attacker.
The arc4rand() function will return very good quality random numbers, slightly better suited for security-related purposes. The random num-
bers from arc4rand() are seeded from the entropy device if it is available. Automatic reseeds happen after a certain timeinterval and after
a certain number of bytes have been delivered. A forced reseed can be forced by passing a non-zero value in the reseed argument.
The read_random() function is used to return entropy directly from the entropy device if it has been loaded. If the entropy device is not
loaded, then the buffer is filled with output generated by random(). The buffer is filled with no more than count bytes. It is advised that
read_random() is not used; instead use arc4rand()
All the bits generated by random(), arc4rand() and read_random() are usable. For example, 'random()&01' will produce a random binary value.
The arc4random() is a convenience function which calls arc4rand() to return a 32 bit pseudo-random integer.
RETURN VALUES
The random() function uses a non-linear additive feedback random number generator employing a default table of size 31 long integers to
return successive pseudo-random numbers in the range from 0 to (2**31)-1. The period of this random number generator is very large, approxi-
mately 16*((2**31)-1).
The arc4rand() function uses the RC4 algorithm to generate successive pseudo-random bytes. The arc4random() function uses arc4rand() to gen-
erate pseudo-random numbers in the range from 0 to (2**32)-1.
The read_random() function returns the number of bytes placed in buffer.
AUTHORS
Dan Moschuk wrote arc4random().
Mark R V Murray wrote read_random().
BSD September 25, 2000 BSD