Using the "alternate screen" in a bash script

You can switch to the alternate screen using this command:

$ tput smcup

And back with:

$ tput rmcup

These commands just output the appropriate escape sequences for your terminal. If it is an XTERM they will be equivalent to the (more known but less elegant or portable):

$ echo -e "\e[?1049h"

And:

$ echo -e "\e[?1049l"

For more terminal control commands see man 5 terminfo.

smcup/rmcup are used, but only for the side effect: the escape sequence which switches between normal/alternate screens is usually embedded in those terminfo capabilities -- not always.

Some background is in the xterm faq Why doesn't the screen clear when running vi?

For C console application:

ncurses

Wikipedia:

ncurses (new curses) is a programming library that provides an API which allows the programmer to write text-based user interfaces in a terminal-independent manner.

less uses this library.

A hello world program from here, to compile it in gcc, flag -lncurses is needed.

#include <ncurses.h>

int main()
{   
    initscr();          /* Start curses mode          */
    printw("Hello World !!!");  /* Print Hello World          */
    refresh();          /* Print it on to the real screen */
    getch();            /* Wait for user input */
    endwin();           /* End curses mode        */

    return 0;
}