/dev/random supplies an seemingly infinite number of random bytes (in fact limited to 32MB since linux 3.16), so your cat won't finish soon if at all,as the random generator won't send an EOF.
Quote:
/dev/random will return at most 512 bytes
(c.f. man random), so you might want to read that, of limit the byte count yourself, e.g. by using
in lieu of cat. Or, why not use bash's $RANDOM variable?
Hi, how do I use /dev/urandom to generate a single number between 1-100? I can od /dev/urandom but it gives me an endless list of random numbers, I just want 1 between 1-100. How can I get that? Thanks. (12 Replies)
Hi, Anyone can help
My solaris 8 system has the following
/dev/null , /dev/tty and /dev/console
All permission are lrwxrwxrwx
Can this be change to a non-world write ??
any impact ?? (12 Replies)
Hi,
Excuse my ignorance here - I'm a networks man and my knowledge of all things unix is somewhat limited.
We have a very large file (/var/tmp/mond.log) that we need to zero - does the "cat /dev/null > /var/tmp/mond.log" command achieve this? (4 Replies)
I am having problems using soundes. Until a few moments ago
the following commands produced errors and no sound:
cat /usr/share/apps/kolf/sounds/blackhole.wav/ > /dev/dsp yielded:
/dev/dsp: Invalid argument
cat /usr/share/apps/kolf/sounds/blackhole.wav > /dev/audio yelded:
/dev/audio:... (3 Replies)
Hello,
I'm trying to send the error output of a 'cat' operation to /dev/null like this:
cat /dirA/dirB/temp*.log > /dirA/dirB/final.log 2>/dev/null
This works perfectly in a terminal, but not when placed in a script.
If there are no files matching temp*.log the script outputs an error... (7 Replies)
i have few log files that are input to my perl script...
i am executing the script as below
cat RTR*.log | test.pl
and getting the following error
-ksh: 25014: Memory fault(coredump)
cat: write error: Connection reset by peer
can anyone help me on this....
Thanks in... (2 Replies)
My AIX-based accounting program runs an end-of-day process that requires all users to be logged out. Sometimes I have a user that leaves for the day and forgets to logout. Is there any way I can cleanly log a user out without killing their process? (4 Replies)
Hi,
In our HP-UX B.11.11. I could not find dev/urandom and dev/random
Are all pseudo-devices implemented as device drivers, or in need to run /configure some package to install the package to have dev/urandom.
Please help (4 Replies)
Discussion started by: rashi
4 Replies
LEARN ABOUT LINUX
mcookie
MCOOKIE(1) Linux Programmer's Manual MCOOKIE(1)NAME
mcookie - generate magic cookies for xauth
SYNOPSIS
mcookie [-v] [-f filename]
DESCRIPTION
mcookie generates a 128-bit random hexadecimal number for use with the X authority system. Typical usage:
xauth add :0 . `mcookie`
The "random" number generated is actually the output of the MD5 message digest fed with various pieces of random information: the current
time, the process id, the parent process id, the contents of an input file (if -f is specified), and several bytes of information from the
first of the following devices which is present: /dev/random, /dev/urandom, files in /proc, /dev/audio.
BUGS
The entropy in the generated 128-bit is probably quite small (and, therefore, vulnerable to attack) unless a non-pseudorandom number gener-
ator is used (e.g., /dev/random under Linux).
It is assumed that none of the devices opened will block.
FILES
/dev/random
/dev/urandom
/dev/audio
/proc/stat
/proc/loadavg
SEE ALSO X(1), xauth(1), md5sum(1)AVAILABILITY
The mcookie command is part of the util-linux package and is available from ftp://ftp.kernel.org/pub/linux/utils/util-linux/.
25 September 1995 MCOOKIE(1)