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Old 10-26-2016, 06:51 AM   #16
RagingRaven
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Quote:
Originally Posted by keefaz View Post
You can put the command in a subshell like
Code:
( command -args "bla" & )
Ok, but do I still need to redirect to /dev/null or not?

So in other words would my line become?:

Code:
( mysql -u${mysqlUser} -p${mysqlPass} -Ae"FLUSH TABLES WITH READ LOCK; SELECT SLEEP(86400)" & )
or?:

Code:
( mysql -u${mysqlUser} -p${mysqlPass} -Ae"FLUSH TABLES WITH READ LOCK; SELECT SLEEP(86400)" & ) > /dev/null 2>&1
Thanks
 
Old 10-26-2016, 06:56 AM   #17
RagingRaven
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Thank you keefaz!

using
Code:
( mysql -u${mysqlUser} -p${mysqlPass} -Ae"FLUSH TABLES WITH READ LOCK; SELECT SLEEP(86400)" & ) > /dev/null 2>&1
I'm finally rid of the output generated.
 
Old 10-26-2016, 06:56 AM   #18
Turbocapitalist
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The latter.

You'll want to look up a little bit about subshells, redirects, and background processes that you are using here. They will be useful in other situations. Some starting points:

http://mywiki.wooledge.org/SubShell
http://mywiki.wooledge.org/BashGuide...ut#Redirection
http://mywiki.wooledge.org/ProcessMa..._background.3F

There is other good reading material elsewhere, too.
 
Old 10-26-2016, 07:08 AM   #19
RagingRaven
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Quote:
Originally Posted by Turbocapitalist View Post
The latter.

You'll want to look up a little bit about subshells, redirects, and background processes that you are using here. They will be useful in other situations. Some starting points:

http://mywiki.wooledge.org/SubShell
http://mywiki.wooledge.org/BashGuide...ut#Redirection
http://mywiki.wooledge.org/ProcessMa..._background.3F

There is other good reading material elsewhere, too.
Thanks Turbo, I'll take a look at it, I understand the basics, but this looks a little more in depth.
 
Old 10-26-2016, 02:59 PM   #20
ondoho
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Quote:
Originally Posted by RagingRaven View Post
Code:
( mysql -u${mysqlUser} -p${mysqlPass} -Ae"FLUSH TABLES WITH READ  LOCK; SELECT SLEEP(86400)" & ) > /dev/null 2>&1
I'm finally rid of the output generated.
yes, but does the script do what it should?
i'm pretty sure that this:
Quote:
Originally Posted by RagingRaven View Post
Just tried with set -e -x and it is indeed the last line that's outputting.
What I did see though was that the command shown was:
Code:
mysql -u<user> -p<pass> '-AeKILL QUERY <id>;'
Which seems different from what's in my code, not only missing the > /dev/null 2>&1 part, but also having single quotes and missing double quotes:
Code:
mysql -u${mysqlUser} -p${mysqlPass} -Ae"KILL QUERY ${SLEEP_ID};" > /dev/null 2>&1
means that there MUST be a space between -Ae and "KILL QUERY ${SLEEP_ID};", so it should read:

Code:
mysql -u${mysqlUser} -p${mysqlPass} -Ae "KILL QUERY ${SLEEP_ID};" > /dev/null 2>&1
try that again.
 
Old 10-26-2016, 04:23 PM   #21
RagingRaven
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@ondoho

Even though there is no space between -e and the query, it does appear to be working fine.


Code:
mysql -u${mysqlUser} -p${mysqlPass} -Ae"FLUSH TABLES WITH READ LOCK; SELECT SLEEP(86400)" &
works because I can see a query running when looking at the processlist.


Code:
mysql -u${mysqlUser} -p${mysqlPass} -Ae"KILL QUERY ${SLEEP_ID};"
also works, because after this command the correct query is no longer running.

So although I agree with you that it looks better to add a space, it doesn't appear necessary

The command itself was never the issue though, that was working fine, it was the output I couldn't get rid of.
Luckily, with a little help from keefaz, it's fixed now though.

Last edited by RagingRaven; 10-26-2016 at 04:26 PM.
 
  


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