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Shell Programming and Scripting

generate random base 16

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Top Forums Shell Programming and Scripting generate random base 16
# 1  
Old 09-18-2012
generate random base 16
How would you use bash to generate a random 32 digit number base 16?

Like this one:

0cc06f2fa0166913291afcb788717458
# 2  
Old 09-18-2012
One way:

Code:
dd count=1024 if=/dev/random 2>/dev/null |md5sum|sed 's/-//'

Not efficient, but it works.
# 3  
Old 09-18-2012
Using bash internals exclusively you can:

Code:
printf "%04x" $RANDOM $RANDOM $RANDOM $RANDOM $RANDOM $RANDOM $RANDOM $RANDOM

edit: oops range of RANDOM is only 0 - 32767; adjusted answer below (not quite so nice)

Code:
for ((i=0;i<10;i++)) {
   printf "%03x" $((RANDOM%4096))
} ; printf "%02x" $((RANDOM%256))

or

Code:
printf "%03x%03x%03x%03x%03x%03x%03x%03x%03x%03x%02x" \
    $((RANDOM%4096)) $((RANDOM%4096)) \
    $((RANDOM%4096)) $((RANDOM%4096)) \
    $((RANDOM%4096)) $((RANDOM%4096)) \
    $((RANDOM%4096)) $((RANDOM%4096)) \
    $((RANDOM%4096)) $((RANDOM%4096)) \
    $((RANDOM%256))

Last edited by Chubler_XL; 09-18-2012 at 10:02 PM..
# 4  
Old 09-18-2012
Code:
x=$(dd if=/dev/random bs=16 count=1 2>/dev/null | od -An -tx1 | tr -d ' \t\n')

Regards,
Alister
# 5  
Old 09-18-2012
Another way
Code:
od -N32 -x < /dev/urandom | head -n1 |  cut -b9- | sed 's/ //gi'

Last edited by Franklin52; 09-19-2012 at 04:58 AM.. Reason: Please use code tags for data and code samples
# 6  
Old 09-19-2012
How about:

Code:
openssl rand -hex 16

This User Gave Thanks to Chubler_XL For This Post:
radoulov
# 7  
Old 09-19-2012
Quote:
Originally Posted by Chubler_XL
How about:
Code:
openssl rand -hex 16

Not good on FreeBSD 6.2-RELEASE FreeBSD (bash)
Gets
Code:
$ openssl rand -hex16
Usage: rand [options] num
where options are
-out file             - write to file
-engine e             - use engine e, possibly a hardware device.
-rand file:file:... - seed PRNG from files
-base64               - encode output
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