-----
#!/bin/sh

awk '/#[0-9]+/ {
	sec	= $1;
	sub(/^#/, "", sec);
	cmd	= "date -d '"'"'@" sec "'"'"' '"'"'+%Y-%m-%d %H:%M:%S'"'"'";
	cmd | getline;
	close(cmd);
	printf("%s  ", $0);
	getline;
	print;
}' "$@"