On Mon, 19 Jun 2017 07:37:35 +0200
Heinz Diehl <htd+ml@xxxxxxxxxx> wrote:
> Pwgen uses /dev/urandom, so the statement that those passwords are
> less secure than "fully" random passwords (define "fully random"..) is
> merely of academical nature.
>
> In case of any doubt, you can always do something like
>
> head /dev/random | tr -dc A-Za-z0-9 | head -c X
>
> where X is your password length. Tr also lets you tailor the
> characterset used.
Here's my shell hack to generate passwords using the above. It saves
the passwords in the file devurandom_password.txt in the home directory.
#! /bin/bash
# generate a password using a character set, /dev/urandom,
# and tr to select the characters included.
# The three arguments are
# the character class to use to generate the password (default alnum)
# and
# the length of the password (default 20)
# and
# the number of passwords to generate (default 10)
DPW=/home/$USER/devurandom_password.txt
if [ "$#" = 0 ]; then
set an 20 10
elif [ "$#" = 1 ]; then
set $1 20 10
elif [ "$#" = 2 ]; then
set $1 $2 10
fi
echo "Passwords from /dev/urandom with $1" > $DPW
echo '' >> $DPW
for ((x = 0 ; x < $3 ; x = x + 1)) ; do
if [ "$1" = an ]; then
echo $(head /dev/random | tr -dc [:alnum:] | head -c $2) >> $DPW
echo '' >> $DPW
elif [ "$1" = al ]; then
echo $(head /dev/random | tr -dc [:alpha:] | head -c $2) >> $DPW
echo '' >> $DPW
elif [ "$1" = cn ]; then
echo $(head /dev/random | tr -dc [:cntrl:] | head -c $2) >> $DPW
echo '' >> $DPW
elif [ "$1" = di ]; then
echo $(head /dev/random | tr -dc [:digit:] | head -c $2) >> $DPW
echo '' >> $DPW
elif [ "$1" = gr ]; then
echo $(head /dev/random | tr -dc [:graph:] | head -c $2) >> $DPW
echo '' >> $DPW
elif [ "$1" = lo ]; then
echo $(head /dev/random | tr -dc [:lower:] | head -c $2) >> $DPW
echo '' >> $DPW
elif [ "$1" = pr ]; then
echo $(head /dev/random | tr -dc [:print:] | head -c $2) >> $DPW
echo '' >> $DPW
elif [ "$1" = pu ]; then
echo $(head /dev/random | tr -dc [:punct:] | head -c $2) >> $DPW
echo '' >> $DPW
elif [ "$1" = sp ]; then
echo $(head /dev/random | tr -dc [:space:] | head -c $2) >> $DPW
echo '' >> $DPW
elif [ "$1" = up ]; then
echo $(head /dev/random | tr -dc [:upper:] | head -c $2) >> $DPW
echo '' >> $DPW
elif [ "$1" = xd ]; then
echo $(head /dev/random | tr -dc [:xdigit:] | head -c $2) >> $DPW
echo '' >> $DPW
else
echo $(head /dev/random | tr -dc [:alnum:] | head -c $2) >> $DPW
echo '' >> $DPW
fi ;
done
exit 0 ;
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