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How to break a loop if condition is met

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# 1  
Old 07-15-2009
Question How to break a loop if condition is met
I am having trouble figuring this code

I want to grep a text from a file and if it match certain text it break out of the loop or it should continue searching for the text

Here is what I have written but it isn't working

Code:
while true
f=`grep 'END OF STATUS REPORT' filename`
do
if [ $f='END OF STATUS REPORT' ]
then
echo Condition match
break
else
echo condition not met still searching
fi
done
echo Condition met and command to execute

There is mistake in the above command and its not working perfectly. appreciate if some one could help me out.

Ismail
# 2  
Old 07-15-2009
The below line is wrong
Code:
if [ $f='END OF STATUS REPORT' ]

Give space on each side of =
And you are not handling
Code:
f=`grep 'END OF STATUS REPORT' filename`

properly... What if more than one line is returned?
and grep will return value with filename so you need to cut the result.

use set -x to debug
# 3  
Old 07-15-2009
Try this:
Code:
f='END OF STATUS REPORT'
while true ; do
   if [ "$f" = "END OF STATUS REPORT" ] ; then
      echo 'Condition match'
      break
   else
      echo 'condition not met still searching'
   fi
done
echo 'Condition met and command to execute'

I changed the first line and removed the "grep" part.
Not sure what you are doing whithout the file "filename".
Last edited by edidataguy; 07-19-2009 at 02:42 AM.. Reason: Reformatted
# 4  
Old 07-15-2009
better you do something like this:

Code:
 
grep 'END OF STATUS REPORT' filename` 2>/dev/null
 
if [ $? -eq 0 ] ; then
.....
....
else
......
.....
fi

# 5  
Old 07-15-2009
thank you all
thank you for all your responses.

edidataguy - I am using a filename. I am using grep to search for text in that file and if the text is found go to a command or else keep on searching for the text.

rakeshawasthi - In my code I giving the result of grep to variable.

panyam - your coding will not keep on searching for the text. I want to continuously to search for the text until its found. then execute a command when its found. The file I am searching is a growing file.

Are there any suggestion or ideas.Smilie
# 6  
Old 07-15-2009
OK. Fix your code as follows and you should be good to go.

while true
do
f=`grep 'END OF STATUS REPORT' filename`
if [ "$f" = "END OF STATUS REPORT" ]

do --> move it up.

f=`grep 'END OF STATUS REPORT' filename` --> move it down.

if [ "$f" = "END OF STATUS REPORT" ] --> Quote both. Gap for =
# 7  
Old 07-15-2009
Code:
while true
do
   f=$( grep 'END OF STATUS REPORT' filename  2>/dev/null )
   # f include data if grep return some string = find something
   # f is empty string if not find 
   # ofcourse you can test exit status: 0=found, != 0  =not
   if [ "$f" != "" ]
   then
           echo Condition match
           break
   fi
   echo condition not met still searching
   sleep 1  # if not so hurry to check under 1 sec, then sleep 1 = system friendly
done

echo Condition met and command to execute

So shortly same result, output is not interesting, only result of grep
Code:
while true
do
   if grep 'END OF STATUS REPORT' filename  >/dev/null  2>&1
   then
           echo Condition match
           break
   fi
   echo condition not met still searching
   sleep 1  
done
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