Test USB drive capacity

test-capacity.sh

#!/bin/bash

if [[ $# -ne 1 ]]
then
  echo "To test for 16G capacity"
  echo "usage: testcap.sh 16"
  exit 1
fi

echo "checking for capacity ${1}G"

for i in `seq 1 1 $1`
do
  cat /dev/urandom | head -c 1G > $i
  md5=$(md5sum $i | cut -c 1-32)
  mv $i $md5
  echo $md5 >> index
  pc=$(echo "scale=1; $i/$1*100" | bc)
  echo "${pc}%"
done

count=0
for entry in $(cat index)
do
  # check file exists
  if [[ ! -f $entry ]]
  then
    echo "file $entry does not exists"
  elif [[ $(md5sum $entry) = $entry ]]
  then
    echo "bad md5sum for file $entry"
  else
    count=$((count+1))
  fi
done

echo "real capacity ${count}G"