Endlessly download a file with wget and verify that its content is unchanged.

dlsum

#!/bin/sh
#
# Endlessly download a file with wget and verify that its content is unchanged.
# Usage: dlsum URL
#

error () {
    echo "Data corruption detected! Here is the diff:"
    mv $filename "${filename}.bad"
    hexdump -C "${filename}.good" > "${filename}.good.hex"
    hexdump -C "${filename}.bad"  > "${filename}.bad.hex"
    diff -Naur "${filename}.good" "${filename}.bad" > "${filename}.diff"
    cat "${filename}.diff" | diff
    exit 1
}

giga=$(expr 1024 \* 1024 \* 1024)

url=$1
[ -z "$url" ] && exit 1

filename=$(basename $url)
filesum="${filename}.md5"

wget -q $url -O $filename
sz=$(stat -c "%s" $filename)
md5sum $filename > $filesum
mv $filename "${filename}.good"

total=0
bound=$giga
for i in $(seq 1 100); do
    wget -q $url -O $filename || break
    md5sum -s -c $filesum || error
    total=$(expr $total + $sz)
    if [ $total -gt $bound ]; then
	printf "%6d GB received\n" $(expr $total / $giga)
	bound=$(expr $bound + $giga)
    fi
    rm -f $filename
done