How to generate a random integer with specific range(for example, from 1 to 1000)?
Also, how to convert a floating point number into a integer? (2 Replies)
I want to be able to generate a random number within a korn shell script..
Preferably i would like to be able to state how many digits should be in this random number... ie 4 digits or 5 digits etc
Any ideas? (2 Replies)
I saw this formula to generate random number between two specified values in shell script.the following.
$(((RANDOM%(max-min+divisibleBy))/divisibleBy*divisibleBy+min))
Give a example in book.
Generate random number between 6 and 30.like this.
$(((RANDOM%30/3+1)*3))
But I have a... (1 Reply)
Dear all,
I have a question. I have a txt file say 4000 rows X 1800 Column. I 'd like to creat a new column as the first column which is a column of random numbers (n=4000)
thanks a lot!
Lin (2 Replies)
Hi,
Do anybody knows how to use awk or any command to random print out 1000 number which start from range 1 to 150000?
I know that "rand" in awk can do similar random selection.
But I have no idea how to write a code that can random pick 1000 number from range 1 to 150000 :confused:
... (1 Reply)
Hi there I am trying to generate a random number between 40 and 70 using the shell here is my code so far and it keeps going above 70. all help much appreciated!
comp=$(( RANDOM%70+40 ))
echo $comp (4 Replies)
Hi,
Is anybody experience generate a pair of random number by using awk command?
I wanna to generate a pair of random number (range from 1 to 4124) and repeats it 416 times.
Desired output
2 326
123 1256
341 14
3245 645
.
.
.
I did write the below command:
awk... (5 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 FREEBSD
read_random
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);
uint32_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