what's "<<" means..?

shrrot · 10-15-2004, 02:11 PM

I know < operation is stdinput..

please explain << operation for example..

and all redirection operation... like 1>, 2>, >&1.. etc..

Cedrik · 10-15-2004, 02:18 PM

All the answers are in :

man bash

example :
Here Documents
This type of redirection instructs the shell to read input
from the current source until a line containing only word
(with no trailing blanks) is seen. All of the lines read
up to that point are then used as the standard input for a
command.

The format of here-documents is:

<<[-]word
here-document
delimiter

shrrot · 10-15-2004, 02:29 PM

thanks to Cedrik..

i find it bash man page...

but..

i don't know how to use...

btmiller · 10-15-2004, 04:18 PM

Well, just read the man page. I'll get you started 2>foo means send all results on file descriptor 2 to the file called foo. In fact n>foo where n is some numbers means send results of file descriptor n to the file called foo. There are three file desctiptors you need to really care about, 0 is standard input, 1 is standard output, and 2 is standard error. 2>&1 means send the output of file descriptor 2 to the same place where 1's output is going ... simple, really, once you know a bit about it.

shrrot · 10-15-2004, 08:01 PM

thanks for your kindness explanation..
your explanatin is helped me understand >, 2>, 2>&1...
but i want to know how to use << ..
i'm sorry my annoying question..