Random password generator, remember a passphrase + unique key (such as sitename)

pw.sh

#!/bin/sh
# Prints out (highly likely at least) 64 random characters, along with some truncations for common password length limits.
# Shows random characters in the printable set as well as just alpha-numeric.

# get rid of -s flag if you want to see what you type
# (possible enhancement for people who typo a lot: read into $p2 as well and only proceed if the entries are equal.)
read -s p
hash=`echo -n $p | sha256sum | sed -e 's/-//' | sed -e 's/ //'`
hash=`python -c "import random, sys, struct; random.seed(0x$hash); bits=[random.getrandbits(64) for i in range(200)]; sys.stdout.write(struct.pack('Q'*len(bits), *bits)); print"`
hash2=`echo $hash | tr -cd "[:graph:]" | head -c ${1:-64}`
hash=`echo $hash | tr -cd "[:alnum:]" | head -c ${1:-64}`

echo '64: '$hash
echo '50: '${hash:0:50}
echo '40: '${hash:0:40}
echo '20: '${hash:0:20}
echo '16: '${hash:0:16}
echo '12: '${hash:0:12}
echo '10: '${hash:0:10}
echo '08: '${hash:0:8}
echo '--'
echo '64: '$hash2
echo '50: '${hash2:0:50}
echo '40: '${hash2:0:40}
echo '20: '${hash2:0:20}
echo '16: '${hash2:0:16}
echo '12: '${hash2:0:12}
echo '10: '${hash2:0:10}
echo '08: '${hash2:0:8}