[Drebin]

pawn Код:

new params[128];
ycmd("/register")
{
     if(!strlen(params))return SendClientMessage(playerid,COLOR_MAIN,"USAGE: /register [password]");
     new string[256];
     format(string,sizeof(string),"%s",params);
     dini_Set(pFile,"Password",string);;
     return true;
}

??
I suggest using ocmd or dcmd + sscanf, but it's your choice