#include <ctype.h>
#include <stdio.h>
#include <signal.h>

#define CTRL_H '\010'
#define CARRIAGE_RETURN '\015'

main(int argc, char *argv[])
{
     FILE *fpin, *fpout;
     int c;
     struct sigaction sa;
     char command[80], outfile[80];
   
     sa.sa_flags = 0;
     sigfillset(&sa.sa_mask);
     sa.sa_handler = SIG_IGN;
     sigaction(SIGINT, &sa, NULL);
     sigaction(SIGQUIT, &sa, NULL);
     sigaction(SIGTSTP, &sa, NULL);

     if (argc != 2)
     {
           printf("Usage: %s infile\n", argv[0]);
           exit(1);
     }

     sprintf(command,"script %s", argv[1]);
     system(command);

     if ((fpin = fopen(argv[1], "r")) == NULL)
     {
           printf("Cannot open input file: %s\n", argv[1]);
           exit(2);
     }
     
     sprintf(outfile, "%s.adgkmx", argv[2]);
     if ((fpout = fopen(outfile, "w+")) == NULL)
     {
           printf("Cannot open output file: %s\n", argv[2]);
           exit(3);
     }
      
     while( (c = fgetc(fpin)) != EOF)
     {
           if (c == CTRL_H)
           {
              fseek(fpout, -1L, SEEK_CUR);
           }
           else if (c == CARRIAGE_RETURN)
           {
              continue;
           }
           else if (iscntrl(c) && !isspace(c))
           {
              continue;
           }
           else
           {
              fputc(c, fpout);
           }
     }     
     rename(outfile, argv[1]);
}