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shell/bash generate random alphanumeric string
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#!/bin/bash | |
# bash generate random alphanumeric string | |
# | |
# bash generate random 32 character alphanumeric string (upper and lowercase) and | |
NEW_UUID=$(cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w 32 | head -n 1) | |
# bash generate random 32 character alphanumeric string (lowercase only) | |
cat /dev/urandom | tr -dc 'a-z0-9' | fold -w 32 | head -n 1 | |
# Random numbers in a range, more randomly distributed than $RANDOM which is not | |
# very random in terms of distribution of numbers. | |
# bash generate random number between 0 and 9 | |
cat /dev/urandom | tr -dc '0-9' | fold -w 256 | head -n 1 | head --bytes 1 | |
# bash generate random number between 0 and 99 | |
NUMBER=$(cat /dev/urandom | tr -dc '0-9' | fold -w 256 | head -n 1 | sed -e 's/^0*//' | head --bytes 2) | |
if [ "$NUMBER" == "" ]; then | |
NUMBER=0 | |
fi | |
# bash generate random number between 0 and 999 | |
NUMBER=$(cat /dev/urandom | tr -dc '0-9' | fold -w 256 | head -n 1 | sed -e 's/^0*//' | head --bytes 3) | |
if [ "$NUMBER" == "" ]; then | |
NUMBER=0 | |
fi |
how do i generate the string cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w 32 | head -n 1 but have the first half as dedicated set characters
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@invisible999 don't know, one needs to make a benchmark with the various proposed methods (and likely others published elsewhere)