January 27, 2026
Headlines

Announcing “liat”, the tail companion

n9sgg03 mins

liat is an application that will List It At the Top!

Try using it as a companion to the legendary tail utility when watching a log file.

It was written to list text that is most recent on the first line (top) and push the rest of the screen down.

Instead of pushing the screen text up after showing the most recent line read from STDIN on the bottom of the screen, liat does the opposite. The most recent line read from STDIN is displayed on the top of the screen and the rest of the text is pushed down on the screen towards the bottom.

The code is available at https://github.com/n9sgg/liat.git

Follow the instructions in the README.md file.

liat requires that the ncurses library be installed before compiling.

The code for V.30 is shown below.

/* ***************************************************************************
* liat.c
* liat - List It At the Top
* Author: Steven G. Lamers 11-19-2019 - ALL RIGHTS RESERVED 2025
* Version: 3.0
* History:
*       1. First beta release - 04-30-2019
*       2. Second release after testing the changes made from V1
*       3. Changed back to read from stdin instead of file 09-25-2025
*       
* Usage example: tail -f <some_file_name> liat 
*
* ************************************************************************* */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <ncurses.h>

#define MAX_LINE_LENGTH 400
#define MAX_LINE_NUMBER 100

void resizeHandler(int);

char  screen[MAX_LINE_NUMBER][MAX_LINE_LENGTH];   /* The screen */
int   height = 0, width = 0;

void main(int argc, char **argv)
{

char  buffer[MAX_LINE_LENGTH] ;   /* line buffer */
int   x         = 0 ;
int   q         = 0 ;

  initscr();

  scrollok(stdscr, TRUE );
   
  getmaxyx(stdscr, height, width);

  if( ( height > MAX_LINE_NUMBER ) || ( width > MAX_LINE_LENGTH ) )
  {
    /* move to 0,0  */
    wmove(stdscr, 0, 0);

    /* clear the line */
    clrtoeol();

    /* print the error */
   wprintw( stdscr, "Sorry, the screen height is %d  the width is %d : MAX_LINE_NUMBER is %d and MAX_LINE_LENGTH is %d \n", 
             height,
             width, 
             MAX_LINE_NUMBER,
             MAX_LINE_LENGTH 
            );
    
    /* Refresh the screen */
    wrefresh(stdscr);
  
  return;
  }

  while(1)
  {

    if (fgets(buffer, MAX_LINE_LENGTH - 1, stdin) != NULL ) {

      wmove(stdscr, height, 0 );

      /* clear the line */
      clrtoeol();  
  
      /* print the line */
      wprintw( stdscr, "%s" , buffer );

      /* Refresh the screen */
      wrefresh(stdscr);
  
      /* push stack down */
      for( q = height - 1; q > 0 ; q-- )
      {
        strcpy( screen[ q ] , screen[ q - 1 ] );      
      }
          
      /* Insert the line at the top of the stack */
      strcpy( screen[ 0 ] , buffer);

      /* Print output */
      for( x=0 ; x < (height - 1);  x++ )
      {                         
        /* move to x,0  */
        wmove(stdscr, x, 0);

        /* clear the current line */
        clrtoeol();          
                      
        /* print the new line */
        wprintw( stdscr, "%s" , screen[ x ] );
            
        /* Refresh the screen */
        wrefresh(stdscr);
      }  
    } else {
            usleep(100000);           // Sleep for 100 milliseconds
    }
  }
  
  endwin();

  return;

} /* end of main () */

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