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Full Discussion: Getting a random file
Top Forums Shell Programming and Scripting Getting a random file Post 302101311 by ripat on Sunday 31st of December 2006 01:07:04 PM
Old 12-31-2006
My version of ksh (1993-12-28 q) doesn't seem to have a limit either. I did a test to assign values to a array in a loop. I gave up at 700,000 elements.

ksh seems to be twice as fast than bash to assign array values. So, I pushed my little benchmark a little bit further and I assigned 10,000 values to an array and randomly accessed that array 1000 times.

Code:
bash
  real    0m0.623s
  user    0m0.500s
  sys     0m0.020s

ksh
  real    0m0.157s
  user    0m0.160s
  sys     0m0.000s

Happy new year to all. Smilie
 

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RANDOM(4)						   BSD Kernel Interfaces Manual 						 RANDOM(4)

NAME
random , urandom -- random data source devices. SYNOPSIS
pseudo-device random DESCRIPTION
The random device produces uniformly distributed random byte values of potentially high quality. To obtain random bytes, open /dev/random for reading and read from it. The same random data is also available from getentropy(2). Using the getentropy(2) system call interface will provide resiliency to file descriptor exhaustion, chroot, or sandboxing which can make /dev/random unavailable. Additionally, the arc4random(3) API provides a fast userspace random number generator built on the random data source and is preferred over directly accessing the system's random device. /dev/urandom is a compatibility nod to Linux. On Linux, /dev/urandom will produce lower quality output if the entropy pool drains, while /dev/random will prefer to block and wait for additional entropy to be collected. With Yarrow, this choice and distinction is not necessary, and the two devices behave identically. You may use either. The random device implements the Yarrow pseudo random number generator algorithm and maintains its entropy pool. The kernel automatically seeds the algorithm with additional entropy during normal execution. FILES
/dev/random /dev/urandom HISTORY
A random device appeared in the Linux operating system. Darwin September 6, 2001 Darwin
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