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So I have a curl that is piped to a grep and a sed. Where would I apply the >/dev/null 2>&1 ?

curl www.site.com | grep stuff | sed "other stuff"

At the very end or after the curl?

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As I said, I want to silence the curl by directing its stdout output and stderr output to /dev/null. –  tzippy Jul 26 '12 at 22:13
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2 Answers

Please be more specific what is the purpose of the command. I guess you want to use

curl -s www.site.com

to prevent the progress indication and other stuff. -s will perform the same action but silently

If you absolutely have to use >/dev/null 2>&1 i think i would redirect curl output to the file

curl www.site.com -o file.txt >/dev/null 2>&1
cat file.txt | grep stuff | sed "other stuff"   
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Thanks. That's what I wanted to achieve. So out of curiousity: Where would the >/dev/null 2>&1 go? –  tzippy Jul 26 '12 at 22:17
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if you do curl www.site.com >/dev/null 2>&1 | grep stuff | sed "other stuff" the grep will receive nothing. If you do curl www.site.com >/dev/null 2>&1 | grep stuff | sed "other stuff" >/dev/null 2>&1 you will not see anything. –  mnmnc Jul 26 '12 at 22:21
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Just explained a bit closer: >/dev/null redirects SDTOUT (standard output) to the "black hole", and 2>&1 appends STDERR (standard error output) to STDOUT so it also goes to Nirvana. This leaves nothing to display: normal output as well as errors are gone. So what you probably may want could be

curl -s www.site.com 2>/dev/null | grep stuff | sed "other stuff"

i.e. not redirecting STDOUT, just suppressing STDERR and telling curl to only show the indended content, then piping that to grep and finally to sed.

Take care to not introduce spaces between "2>", or the 2 would rather be interpreted as additional parameter to curl ;)

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