7 echo 'Usage: $0 <url> [<target>]' >&2
8 # download url to target location if modified
13 target=${2:-${source##*/}}
17 modified=$(stat -c%y -L "$target") &&
18 modified=$(date -R -d "$modified")
19 echo download since: $modified
22 headers=${modified:+If-Modified-Since: $modified}
23 wget -nv --header="$headers" -O "$target.new" "$source" &&
24 mv "$target.new" "$target" ||
25 rm "$target.new" # clean up failed download (usually empty 304 response)