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Shell Programming and Scripting

I/O redirection

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# 15  
Old 03-09-2011
Interesting data and I'm glad you caught my error. But this still leaves the original question up in the air. What are your thoughts on the example the OP asked about? There doesn't seem to be much hope of saving it. Smilie
# 16  
Old 03-10-2011
Quote:
Originally Posted by Perderabo
Interesting data and I'm glad you caught my error. But this still leaves the original question up in the air. What are your thoughts on the example the OP asked about? There doesn't seem to be much hope of saving it. Smilie
I don't know, I asked on c.u.s., this is the releveant part of the Advanced Bash-Scripting Guide:

Code:
# Redirecting only stderr to a pipe.  
exec 3>&1                              # Save current "value" of stdout. 

ls -l 2>&1 >&3 3>&- | grep bad 3>&-    # Close fd 3 for 'grep' (but not 'ls'). #              
               ^^^^   ^^^^
exec 3>&-                              # Now close it for the remainder of the script.  

# Thanks, S.C.

I think S.C. stands for Stephane Chazelas, he's one of the most respected contributors there on c.u.s. (comp.unix.shell).

---------- Post updated at 11:05 AM ---------- Previous update was at 07:41 AM ----------

Got an answer from Icarus Sparry.
This User Gave Thanks to radoulov For This Post:
homeboy
# 17  
Old 03-10-2011
Quote:
Originally Posted by Icarus Sparry
The "3>&-" just to the left of the comment does close fd 3 for grep but not ls. There is a second 3>&- just to the left of the pipe that closes it for the shell that will turn into ls.
Wow. Duh! That seems so obvious now. Personally, I wasn't able to make sense out of "# Close fd 3 for 'grep' (but not 'ls'). #" because I took it as referring to the entire pipeline, not just the final component (just like, I suspect, the OP).

It wasn't going to keep me up at night, but thank you, radoulov, for showing us the way out of the box Smilie

Regards,
Alister
# 18  
Old 03-10-2011
Quote:
Originally Posted by alister
Wow. Duh! That seems so obvious now. Personally, I wasn't able to make sense out of that comment because I interpreted took it as referring to the entire pipeline, not just the final component (just like, I suspect, the OP).
Me too Smilie

Quote:
It wasn't going to keep me up at night, but thank you, radoulov, for showing us the way out of the box Smilie
You're welcome Smilie
# 19  
Old 03-10-2011
Thanks all of you,you guys are so kind!!And i love this forum more because of you guys!
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