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Use grep result to execute next command

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# 1  
Old 02-16-2009
Use grep result to execute next command
Hi I am trying to run 2 servers using a script one after the other.

I start the first one:

Code:
run.sh -c servername >> jboss_log.txt &

Then I have to wait until I see Started message in the log file before I launch the other server.

I can't use sleep because I am not sure how long it'll take for the server to startup. So I need something like

Code:
while (true) {
if [tail -f jboss_log.txt | grep Started ] //meaning when it was found
then 
   break
fi
}

start the next command

obviously this doesn't work,

any hint on how I could write something like this?


Thanks in advance
# 2  
Old 02-16-2009
Code:
run.sh -c servername >> jboss_log.txt &
wait $!

# 3  
Old 02-16-2009
Thanks for the reply,

however wait$! doesn't work because
run.sh -c servername >> jboss_log.txt &

is never terminated, never returns, it keeps writing to boss_log.txt forever. So my 2nd server doesn't start.
# 4  
Old 02-16-2009
So far I have

Code:
      5 
      6 
      7 while [ 1 ]
      8 do
      9 
     10    myvar= fgrep -c 'Started in' jboss_log.txt
     11 
     12    echo $myvar
     13 
     14   if [ $myvar==1 ]
     15   then
     16       echo "JBoss was launched successfully"
     17         break
     18       fi
     19       sleep 1
     20     done

But the if statement is always true even thou line 12 prints 0.
Can anyone tell me why?
# 5  
Old 02-16-2009
Quote:
Originally Posted by iririr
So far I have

Code:
      5 
      6 
      7 while [ 1 ]


The standard idiom is:

Code:
while :

Or:

Code:
while true

Quote:
Code:
      8 do
      9 
     10    myvar= fgrep -c 'Started in' jboss_log.txt


Syntax error. There can be no space after the equals sign.
Quote:
Code:
     11 
     12    echo $myvar
     13 
     14   if [ $myvar==1 ]


That will always be true as you are testing a non-empty string. There is no test operator in that statement.

And the test for numerical equality is -eq:

Code:
if [ $myvar -eq 1 ]

Quote:
Code:
     15   then
     16       echo "JBoss was launched successfully"
     17         break
     18       fi
     19       sleep 1
     20     done

But the if statement is always true even thou line 12 prints 0.
Can anyone tell me why?
# 6  
Old 02-16-2009
Thanks a lot for your help.

I fixed it :


while [ 1 ]
do
myvar=`fgrep -c 'Started in' jboss_log.txt`

if [ "$myvar" -eq "1" ]
then
echo "JBoss was launched successfully"
break
fi
sleep 5
done
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