multiple grep of file

[hubud]

I have a script that analyses a list of files checking for various values and then reporting on this. I have just added a couple more greps to the script and it is now running in about 12 secs rather than the 2-3 it was before.

If a file is grepped and then grepped again straight away, does it use a cached copy of the file or re-read from the file on disk?

this may explain the time it takes to run

cheers

simmo

 

[PHV]

Can you post the script if you want some advices, please.

Hope This Help, PH.
Want to get great answers to your Tek-Tips questions? Have a look at FAQ219-2884

 

[hubud]

space=' '
ls -1rt | tail -170 > $file


while read filename
do

tail -1 $filename | grep "failure" > /dev/null 2>&1

if [ $? = 0 ]
then

var1=`grep 'Initializing session' $filename`
var2=`echo $var1 | cut -d[ -f3`
var3=`echo $var2 | cut -d' ' -f1,3,4`

echo "$var3-- $filename: failed" >> $failures

grep "^ORA" $filename > /dev/null 2>&1

if [ $? = 0 ]
then
echo "$space Root cause; May have failed due to an ORA error" >> $failures
fi
grep "No such file or directory" $filename > /dev/null 2>&1

if [ $? = 0 ]
then
echo "$space Root cause; Source file not present" >> $failures
fi


#############################
#loads of greps on same file using same syntax
#############################

else
grep "^ORA" $filename > /dev/null 2>&1

if [ $? = 0 ]
then
echo "$filename: Failed due to an Ora error not detected by Informatica" >> $failures2
fi
fi


done<$file

Is this a bad way to do this?

cheers

simmo

 

[sbix]

It's better to use awk for tasks like this.