get it to seen next time after game open is easy with
file=file_open_read("valoda.dat");
and further information can get with file_str_read(file,string);//and other ways because it stops in , and other stupid simbols and in this case you can use read_to!
Example:

val_dok = file_open_read("valoda.dat"); // open language file
valoda = file_var_read(val_dok); //read which language is set
file_close(val_dok);
varonis_dat = file_open_read("varonis.dat"); // open info file
file_find(varonis_dat,"Vards:");//find this name and put cursor behind it
file_str_readto(varonis_dat,strIevadesfin,",IP:",null);//read name till "IP:" text!
file_find(varonis_dat,"IP:");//find this text and put cursor behind it
file_str_read(varonis_dat,strIP); // and read which IP is inputted
file_close(varonis_dat);

In this way you can read any text from start till your own maded end string.

And now how to do this writing in game time from my opinion:

function input_check
{
if(str_len(txt_str)=10)
{str0=create_string("#10");
str0.sring=txt_str;//set second string pos to first string
inkey_active=off;
//and now first to next line
txt_str=str0.pos_y+str0.char_y;//if need put some more pixels
str_cpy(txt_str,"");
input();
}
}

funtion input
{
input_check();
inkey(txt_str);
//after enter
fails=file_open_write(fails.dat);//save result
file_str_write(fails,txt_str);//use if or anything else to check other maded or defined strings
file_str_read(fails,"!END#$%");//your read end part to let read all commas and other stupid reading breakers.
file_close(fails);
}

for short version is good, but much to improve(almost not tested, but if you know how to do programming all will be good).