> > someone could tell me what characters ( eg. ^[[2J^[[0;0H ) means ?? what > > I know is, when I run it, two blue bands with the text wrote in red > > in middle appeared... > > I believe these are ansi codes. Somewhere there exists documentation > for it but I don't have some handy. You might want to let archie > or a webcrawler search for it.
ESC[2J is clear screen, ESC[0;0H is move to coordinates (0,0).. which should be unnecessary since the cursor should go there anyway when the screen clears.