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bash while loop

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Last Modified: 2014-11-18
Wish I knew how to do this on my own but I've wasted too much time on it as it is.... help! No idea what syntax to use.

I need to make the while condition a curl test to see if I get a result 200.
If I don't, then loop again until I do.
Once I do, then continue on with the script.

#!/bin/bash

while "curl -m 5 -k --key sever.key --cert server.crt -u "user:1234" -s -o /dev/null -w '%{http_code}\n' https://google.com)" ;
                if [  $RES -ne 000 ];then echo "AVAILABLE" ; fi
         do
        sleep 2
    done

echo "would continue with the script from this point on..."
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Most Valuable Expert 2013
Top Expert 2013

Commented:
"while" must be followed by "do". So just exchange "do" and "if ..."

while <operation>
   do
        if <condition> ; then
        <operation>
        fi
        sleep
   done

Your script has to fill the "RES" variable some way. Perhaps like this:

while RES=$(curl -m 5 -k --key sever.key --cert server.crt -u "user:1234" -s -o /dev/null -w '%{http_code}\n' https://google.com))
 do
   if [  $RES -eq 200 ];then 
       echo "AVAILABLE" ; 
       break
   fi
   sleep 2
done

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The while loop will run as long as the curl command (which I didn't check for syntax, by the way) gives a zero return code and the outcome is not equal 200.
Should curl fail or should the result be 200 the loop will terminate and the script will continue after "done".
To check whether the loop ended due to "curl" having failed or due to RES being 200 best repeat the test for "$RES -eq 200" after "done" and react accordingly.
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Most Valuable Expert 2013
Top Expert 2013

Commented:
If you want to run the loop until you're getting a 200 regardless of whether curl fails or not try this:

while :
  do
   RES=$(curl -m 5 -k --key sever.key --cert server.crt -u "user:1234" -s -o /dev/null -w '%{http_code}\n' https://google.com))
   if [  $RES -eq 200 ];then 
       echo "AVAILABLE" ; 
       break
   fi
   sleep 2
done

Open in new window


":" means "no operation" which always returns "true", so the loop will run until the break condition ("200") is met.
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Commented:
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Most Valuable Expert 2013
Top Expert 2013

Commented:
I assumed that the RES variable is needed again later in the script and that issuing the "Available" message is mandatory .

Author

Commented:
Basically, I just don't want the rest of the script to run until I can see the server and get a curl 200 result back.
To just keep trying until I see a 200 then continue on with the script.

Currently, I am using something like this;

#!/bin/bash

    while [[ $(date "+%Y") -lt 2000 ]] ;
         do
        sleep 10
    done

This simply lets me know once my device time was updated, which means I now have internet access.
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Top Expert 2013

Commented:
All of our solutions will do what you desire.

Author

Commented:
I'm not sure which one is what I need then.

I do need to know that I am getting a 200 back because that confirms that the script is able to see the target before continuing on.
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Author

Commented:
/go: line 3: [: 000: unary operator expected
not seeing some site yet so try again until I see it
./go: line 3: [: 000: unary operator expected
not seeing some site yet so try again until I see it
./go: line 3: [: 000: unary operator expected

#!/bin/bash

until [ $(curl -s -o /dev/null -w '%{http_code}\n' https://google.com) -eq200 ]
do
     sleep 2

echo "not seeing some site yet so try again until I see it"

done

Echo "now would continue with the script"
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Most Valuable Expert 2013
Top Expert 2013

Commented:
Put a space between "-eq" and "200"

until [ $(curl -s -o /dev/null -w '%{http_code}\n' https://google.com) -eq 200 ]
do

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