Exit for loop in a shell script if a condition is successfull

usha rao · #1 (**permalink**) 05-10-2009

Hi All,
I am stuch in a script where a for loop is running to execute some commands for some values.
Now my problem is i have to have an if condition that if the first iteration is successful then it has to exit the for loop otherwise it has to continue normally.

my code is this:

Code:

 
for jvm in `cat /tmp/highcpu | awk -F" " '{print $3}' | sed 's/Cl/\/Cl/g'`;do
for val in `cat /tmp/thrd_id`;do
cd /logs/$jvm
echo "Thread location is $jvm and thread id is $val" >> /tmp/thread_causing_problem
cat websphere_stdout.txt |sed -n "/$val/,/\"/p"  >> /tmp/thread_causing_problem
done
done

What i have tried so far is

Code:

 
for jvm in `cat /tmp/highcpu | awk -F" " '{print $3}' | sed 's/Cl/\/Cl/g'`;do
for val in `cat /tmp/thrd_id`;do
cd /logs/$jvm
echo "Thread location is $jvm and thread id is $val" >> /tmp/thread_causing_problem
cat websphere_stdout.txt |sed -n "/$val/,/\"/p"  >> /tmp/thread_causing_problem
if [ $? -eq 0 ]; then
exit 1;
fi
done
done

but it is not working.

I have other way
like this

Code:

if [ !-s /tmp/thread_causing_problem ] ; then

but this will not help as the line

Code:

echo "Thread location is $jvm and thread id is $val"

will execute even if

Code:

cat websphere_stdout.txt |sed -n "/$val/,/\"/p"  >> /tmp/thread_causing_problem

will not return any value.

My requirement is the for loop should execute only once if for the first iteration

Code:

 
cat websphere_stdout.txt |sed -n "/$val/,/\"/p"  >> /tmp/thread_causing_problem

the above line produces an out put.
If the above line produces an output for the first iteration then there is no need of doing further iteration and it should exit the for loop else it should continue executing the loop.

Can anyone help??

Thanks in advance

TonyFullerMalv · #2 (**permalink**) 05-10-2009

Replace your exit with break.

usha rao · #3 (**permalink**) 05-11-2009

Hi Tony,
Thanks for your quick reply.
But my problem is

this code

Code:

 
cat websphere_stdout.txt |sed -n "/$val/,/\"/p"  >> /tmp/thread_causing_problem

even if it doesnt return anything then also

[ "$?" -eq 0] will be true.

How to tackle this

My requirement is if for the first iteration i get some output in /tmp/thread_causing_problem file.
It should exit both the for loops....

How to do that??

Thanks in advance

kerrylinux · #4 (**permalink**) 05-11-2009

From the top of my head I would store the output and check, if it is zero.

Something like this should work:

Code:

OUTPUT=$(cat websphere_stdout.txt |sed -n "/$val/,/\"/p")
if [[ x${OUTPUT} != "x" ]];then
         echo $OUTPUT >> tmp/thread_causing_problem
else
         exit 7
fi

Hope that helps.

usha rao · #5 (**permalink**) 05-13-2009

Hi Kerrylinux,
Thanks a lot for your reply and sorry for delay in reply.

but while executing the script it is giving like this:

Code:

./operating_check.ksh[68]: tmp/thread_causing_problem: cannot create

The code snippet which you have given i have to use it in a loop like i have specified earlier like this:

Code:

for jvm in `cat /tmp/highcpu | awk -F" " '{print $3}' | sed 's/Cl/\/Cl/g'`;do

for val in `cat /tmp/thrd_id`;do

cd /logs/$jvm
echo "Thread location is $jvm and thread id is $val" >> /tmp/thread_causing_problem
OUTPUT=$(cat websphere_stdout.txt |sed -n "/$val/,/\"/p")
if [[ x${OUTPUT} != "x" ]];then
         echo $OUTPUT >> tmp/thread_causing_problem
else
         exit 7
fi
done
done

and what is the significance of exit 7???

as specified by Tony whether i have to use use exit or break??

Please advice...
Thanks

kerrylinux · #6 (**permalink**) 05-15-2009

but while executing the script it is giving like this:

Code:

./operating_check.ksh[68]: tmp/thread_causing_problem: cannot create

Sorry, a / got lost, you should write your warning message to /tmp/... of course

I suggested to use exit, because you said that you'd like to exit both loops.
The number following exit is only a return code and allows to distinguish different exit statements, if you leave your script for different reasons.

If you have to continue your script after exiting your two loops, then use break to leave the first one and set a Flag (F="error") to signal the embracing loop that it has to end as well.

Code:

for jvm in ... ; do
       for val in ... ; do

               #  use break here and set flag
       done
       if [[ $F = "error" ]];then
           break
       fi
done

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