/dev/fd question
 

what exactly is going on in this piece of code? what is the role of /dev/fd? i know that /dev/fd/0 is somehow linked to standard input, but that's the extent of my knowledge

http://www.informit.com/articles/art...eqNum=15&rll=1

The above link explains /dev/fd. Generally /dev/fd/ has an entry for stdin, stdout, and stderr. stdin is /dev/fd/0.

Therefore, your code cats a file called header.txt, followed by stdin, followed by the file footer.txt, one after the other. It is the equivalent to:

cat header.txt - footer.txt

where the dash in the middle signifies stdin.

Sasha

the explanation in the link is almost exactly the same as the one given in the manual i'm reading. i'm afraid i still don't understand it.

ok i think i have the /dev/fd/0 figured out. i have another question, still related to re-direction. what's the difference with:

and