UNIX

 f1 = efopen(argv[1], "r");

 f2 = efopen(argv[2], "r");

 fout = efopen("idiff.out", "w");

 mktemp(diffout);

 sprintf(buf, "diff %s %s >%s", argv[1], argv[2], diffout);

 system(buf);

 fin = efopen(diffout, "r");

 idiff(f1, f2, fin, fout); unlink(diffout);

 printf("%s output in file idiff.out\n", progname);

 exit(0);

}

idiff(f1, f2, fin, fout) /* process diffs */

 FILE *f1, *f2, *fin, *fout;

{

 char *tempfile = "idiff.XXXXXX";

 char buf[BUFSIZ], buf2[BUFSIZ], *mktemp();

 FILE *ft, *efopen();

 int cmd, n, from1, to1, from2, to2, nf1, nf2;

 mktemp(tempfile);

 nf1 = nf2 = 0;

 while (fgets(buf, sizeof buf, fin) != NULL) {

  parse(buf, &from1, &to1, &cmd, &from2, &to2);

  n = to1-from1 + to2-from2 + 1; /* #lines from diff */

  if (cmd == 'c')

   n += 2;

  else if (cmd == 'a')

   from1++;

  else if (cmd == 'd')

   from2++;

  printf("%s", buf);

  while (n-- > 0) {

   fgets(buf, sizeof buf, fin);

   printf("%s", buf);

  }

  do {

   printf("? ");

   fflush(stdout);

   fgets(buf, sizeof buf, stdin);

   switch (buf[0]) {

   case '>':

    nskip(f1, to1-nf1);

    ncopy(f2, to2-nf2, fout);

    break;

   case '<':

    nskip(f2, to2-nf2);

    ncopy(f1, to1-nf1, fout);

    break;

   case 'e':

    ncopy(f1, from1-1-nf1, fout);

    nskip(f2, from2-1-nf2);

    ft = efopen(tempfile, "w");

    ncopy(f1, to1+1-from1, ft);

    fprintf(ft, "--- \n");

    ncopy(f2, to2+1-from2, ft);

    fclose(ft);

    sprintf(buf2, "ed %s", tempfile);

    system(buf2);

    ft = efopen(tempfile, "r");

    ncopy(ft, HUGE, fout);

    fclose(ft);

    break;

   case '!':

    system(buf+1);

    printf("!\n");

    break;

   default:

    printf("< or > or e or !\n");

    break;

   }

  } while (buf[0]!= '<' && buf[0]!= '>' && buf[0]! = 'e');

  nf1 = to1;

  nf2 = to2;

 }

 ncopy(f1, HUGE, fout); /* can fail on very long files */

 unlink(tempfile);

}

parse(s, pfrom1, pto1, pcmd, pfrom2, pto2)

 char *s;

 int *pcmd, *pfrom1, *pto1, *pfrom2, *pto2;

{

#define a2i(p) while (isdigit(*s)) \

 p = 10*(p) + *s++ - '0'

 *pfrom1 = *pto1 = *pfrom2 = *pto2 = 0;

 a2i(*pfrom1);

 if (*s == ',') {

  s++;

  a2i(*pto1);

 } else

  *pto1 = *pfrom1;

 *pcmd = *s++;

 a2i(*pfrom2);

 if (*s == ',') {

  s++;

  a2i(*pto2);

 } else

  *pto2 = *pfrom2;

}

nskip(fin, n) /* skip n lines of file fin */

 FILE *fin;

{

 char buf[BUFSIZ];

 while (n-- > 0)

  fgets(buf, sizeof buf, fin);

}

ncopy(fin, n, fout) /* copy n lines from fin to fout */

 FILE *fin, *fout;

{

 char buf[BUFSIZ];

 while (n-- > 0) {

  if (fgets(buf, sizeof buf, fin) == NULL)

   return;

  fputs(buf, fout);

 }

}

#include "efopen.c"

3.8.28 makefile

files: files.o files1.o directory.o

      cc files.o files1.o directory.o -o files

p0: p0.c ttyin0.c

      cc p0.c ttyin0.c

clean:

      rm -f *.o a.out

3.8.29 newer

# newer f: list files newer than f

ls -t | sed '/^'$1'$/q'

3.8.30 news1

# news: print news files, version 1

HOME=. # debugging only