FS utils treates directories as files?

[Thomas Backman]

On Jun 9, 2009, at 11:03 AM, Ivan Voras wrote:

> Thomas Backman wrote:
>> FreeBSD 8.0-CURRENT r193521 (Jun 5), bash:
>> [root at chaos /usr/ports]# file /
>> /: directory
>> [root at chaos /usr/ports]# cat /
>> �g��=[root at chaos /usr/ports]#
>> [root at chaos /usr/ports]# cat /usr/ports/mail
>> �
>
> This is the traditional behaviour because yes, directories are just
> simply ordinary files with a special bit set to distinguish them.  
> Other
> systems might have modified "cat" to check if directories are files  
> but
> it's not standard.
>
> You can easily check this yourself. The following small program should
> work on every unix-ish system:
>
> #include <stdio.h>
> #include <stdlib.h>
> #include <sys/fcntl.h>
>
> int main() {
> 	int fd, i;
> 	char buf[512];
> 	
> 	fd = open(".", O_RDONLY);
> 	read(fd, buf, 512);
> 	for (i = 0; i < 512; i++)
> 		printf("%4d ", buf[i]);
> }

Yes, I realize that, and actually added a stat() call to cat to check  
for directories... before I realized it was true for other utils as  
well.
I still think it's weird, though, and that the utils should check (as  
long as they return gibberish; less /etc on my GNU/Linux system  
actually shows a readable list of files - it seems as if less /etc ==  
ls -al /etc | less). Is there *any* use for this behaviour, or is it  
simply there because nobody has added a check?

Regards,
Thomas