Convert clear passwords into slightly more generalised brute force masks for hashcat mode -a3

inplace-maskgen.sh

#!/bin/sh
file="$1"
tmp=$(mktemp)

# change specials & digits to hashcat format
sed -e "s/[[:punct:]]/?s/g" \
    -e "s/[[:digit:]]/?d/g" \
    $file \
    > $tmp \
&& \
# sort them most frequent to least and unique them
sort $tmp \
| uniq -c \
| sort -rn \
| sed "s/^[\ 0-9]* //" \
  > $file.singemasks \
&& rm $tmp