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Commands tagged /dev/urandom from sorted by
Terminal - Commands tagged /dev/urandom - 7 results
base64 /dev/urandom | head -c 33554432 | split -b 8192 -da 4 - dummy.
8

Avoiding a for loop brought this time down to less than 3 seconds on my old machine. And just to be clear, 33554432 = 8192 * 4086.

for i in {1..4096}; do base64 /dev/urandom | head -c 8192 > dummy$i.rnd ; done
1

Using the 'time' command, running this with 'tr' took 28 seconds (and change) each time but using base64 only took 8 seconds (and change). If the file doesn't have to be viewable, pulling straight from urandom with head only took 6 seconds (and change)

for i in `seq 1 4096`; do tr -dc A-Za-z0-9 </dev/urandom | head -c8192 > dummy$i.rnd; done
genpassdeep() { cat /dev/urandom | tr -dc [:alnum:] | head -c64 | whirlpooldeep; echo; }
2012-11-11 19:19:29
User: malathion
Functions: cat head tr
-2

/dev/urandom relies on operator input to set the random seed. By itself, this may not contain enough random bits to produce high entropy output, especially if the system was recently restarted. Therefore, key stretching through a hash reduces the risk of using low-entropy output as a security key.

genpassdeep() { cat /dev/urandom | tr -dc [:alnum:] | head -c64 | sha256deep; echo; }
2012-11-09 00:33:22
User: malathion
Functions: cat head tr
-1

/dev/urandom relies on operator input to set the random seed. By itself, this may not contain enough random bits to produce high entropy output, especially if the system was recently restarted. Therefore, key stretching through a hash reduces the risk of using low-entropy output as a security key.

cat /dev/urandom|od -t x1|awk 'NR > line { pos=int(rand()*15)+2;printf("%s",$pos);line=NR+(rand()*1000);digits = digits+2 } digits == 64 { print("\n");exit }'
2012-08-14 19:02:00
User: jetdillo
Functions: awk cat exit od
1

Use this the next time you need to come up with a reasonably random bitstring, like for a WPA/WPA2 PSK or something. Takes a continuous stream of bytes coming from /dev/urandom, runs it through od(1), picking a random field ($0 and $1 excluded) from a random line and then prints it.