/dev/urandom is not specified by POSIX. So, besides being ugly, it doesn't really conform to POSIX.
Hmmm, I didn't know that and it looks like there are very many on the WWW that don't either as that was where I got my main info from; that means that /dev/random is not POSIX compliant either. Ouch!
Quote:
The shell variable RANDOM is not specified by POSIX either, but if you're using ksh or bash, the following code is a LOT faster and simpler:
I already have this and Shell Check pointed out that RANDOM is undefined that is why I went the direction that I did.
Quote:
Note that on many systems, /bin/sh is not a POSIX-conforming shell. And, as you have seen in many of my earlier posts, /bin/awk or /usr/bin/awk might not be a POSIX-conforming awk utility. But as long as /bin/sh is a shell that recognizes Bourne shell syntax, the following usually works on any POSIX-conforming system:
There is other implementation-defined initialization code that is needed on some systems to really set up a POSIX-conforming environment, but the above should work for the minimal features used by this script.
Hmm, awk again, why did I not think of that after all I use it a lot for floating point stuff for CygWin...
You are a star Don thanks, consider my ugly non-compliant code scrubbed I am homing in on your 'awk' example...
This POSIX lark is much more difficult than I expected.
As for your final part about 'awk', if one does not use extensions that are not POSIX compliant then surely that particular 'awk' variant IS still technically conforming to the POSIX _environment_?
---------- Post updated at 11:57 AM ---------- Previous update was at 10:02 AM ----------
As an addendum here I decided to make it look a little clearer for me so I put this into Shell Check...
And got this _error_:-
Do I take it that Shell Check is correct and the backslash is a no-no even inside a completely different language; the above works perfectly for my needs.
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)