Last 5 - get the last 5 characters from each line of a text file. From http://www.thelinuxrain.com/articles/bash-drivers-start-your-engines

last5.c

#include <stdio.h>
#include <stdlib.h>

// from http://www.thelinuxrain.com/articles/bash-drivers-start-your-engines
// C version is about 2-4 times faster than perl version.

int main (int argc, char *argv[])
{
  if (argc != 2){
    printf("Usage: %s filename\n", argv[0]);
    exit(1);
  }
  FILE *fp;
  if ((fp = fopen(argv[1],"r"))==NULL){
    printf("Can not open file %s \n",argv[1]);
    exit(1);
  }

  char *line = NULL;
  size_t len = 0;
  ssize_t read;
  
  while ((read = getline(&line, &len, fp)) != -1 ) {
        if (len>5){
           printf("%s", line + read - 6);
        }
  }
  free (line);
  fclose(fp);
}

C version: 1.28s
awk version: 25.29s
perl version: 4.79s