getvar() {
eval "echo \"\${$1}\""
}
var2file() {
local var
eval "var=\"\${$1}\""
if [ -n "$var" ]; then echo "$var" > "$2"; fi
isset() {
[ -n "$var" ]
md5s() {
cat "$@" | (
md5sum 2>/dev/null ||
md5
) | awk '{print $1}'