private boolean first = true;
public TailCommand() {
super("Print the tail end of a list of files, or stdin.");
Files = new FileArgument("files", Argument.OPTIONAL | Argument.MULTIPLE, help_files);
Bytes = new StringArgument("bytes", Argument.EXISTING | Argument.OPTIONAL, help_bytes);
Lines = new StringArgument("lines", Argument.EXISTING | Argument.OPTIONAL, help_lines);
Follow = new FlagArgument("follow", Argument.OPTIONAL, help_follow);
FollowR = new FlagArgument("followr", Argument.OPTIONAL, help_follow_retry);
MaxUnchanged = new IntegerArgument("unchanged", Argument.OPTIONAL, help_unchanged);
Sleep = new IntegerArgument("sleep", Argument.OPTIONAL, help_sleep);
Retry = new FlagArgument("retry", Argument.OPTIONAL, help_retry);