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?
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 ${SEED%.*}
Now, in online examples... (4 Replies)
Hello All, I am stuck up in a program where the rand functions ends up giving all the same integers. Tried sleep, but the numbers turned out to be same... Can anyone help me out how to fix this issue ? I have called the srand once in the program, but I feel like when I call fork the child process... (5 Replies)
Hi there I am trying to generate a random number between 40 and 70 using the shell here is my code so far and it keeps going above 70. all help much appreciated!
comp=$(( 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 all...
Apologies for any typos, etc...
This took a while but it didn't beat me...
Although there are many methods of generating random numbers in a POSIX shell this uses integer maths and a simple C source to create an executable to get epoch to microseconds accuracy if it is needed. I take... (8 Replies)
Discussion started by: wisecracker
8 Replies
LEARN ABOUT MOJAVE
rand
RAND(3) BSD Library Functions Manual RAND(3)NAME
rand, rand_r, srand, sranddev -- bad random number generator
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <stdlib.h>
int
rand(void);
int
rand_r(unsigned *seed);
void
srand(unsigned seed);
void
sranddev(void);
DESCRIPTION
These interfaces are obsoleted by arc4random(3).
The rand() function computes a sequence of pseudo-random integers in the range of 0 to RAND_MAX (as defined by the header file <stdlib.h>).
The srand() function sets its argument seed as the seed for a new sequence of pseudo-random numbers to be returned by rand(). These
sequences are repeatable by calling srand() with the same seed value.
If no seed value is provided, the functions are automatically seeded with a value of 1.
The sranddev() function initializes a seed, using the random(4) random number device which returns good random numbers. However, the rand()
function still remains unsuitable for cryptographic use.
The rand_r() function provides the same functionality as rand(). A pointer to the context value seed must be supplied by the caller.
SEE ALSO arc4random(3), random(3), random(4)STANDARDS
The rand() and srand() functions conform to ISO/IEC 9899:1990 (``ISO C90'').
The rand_r() function is as proposed in the POSIX.4a Draft #6 document.
BSD May 25, 1999 BSD