Add this line to the top of update.c 
void write_whofile();

add this someone in hte updating function
write_whofile ();

then add the following to the end of update.c
you will also have to define WHOFILE in mud.h or wherever, i put mine in the system Direcotory, do yers wherever you want :)
PS I appoligize for the formatting of this, but debain is wierd with it :P

/*
* This code is for the who output for us to see who's on in the shell.. :)
* -Gangien
*/

void write_whofile()
{
DESCRIPTOR_DATA *d;
int count;
FILE *fp;
char buf[MAX_STRING_LENGTH];


fprintf(fp, "\nDesc|Con|Idle| Port | Player      @HostIP           ");
fprintf(fp, "| Username");
fprintf(fp, "\n");
fprintf(fp, "----+---+----+------+-------------------------------");
fprintf(fp, "+---------");
fprintf(fp, "\n");

for ( d = first_descriptor; d; d = d->next ) {
count++;
sprintf( buf,
" %3d| %2d|%4d|%6d| %-12s@%-16s ",
d->descriptor, d->connected, d->idle / 4, d->port,
d->original  ? d->original->name  : 
d->character ? d->character->name : "(none)", d->host);
sprintf( buf + strlen( buf ), "| %s", d->user );
strcat(buf, "\n");
fprintf(fp, buf );
}
fprintf( fp, "%d user%s.\n", count, count == 1 ? "" : "s" );
fclose(fp);
return;
}