grep in a loop

Shell Programming and Scripting
1

Hi ,

I am trying a script which takes user input userid . I am stuck how to check whether that is a valid user id or not in the audit log files. My code is :

cd $CCP_AUDIT
cat * > /export/home/$USR/l***/files
echo "UserId:\c"
read UserId

#Date Function
echo "DATE [YYYY-MM-DD] : \c"
read xxx

I need help in putting this in a loop:

grep $xxx /export/home/$USR/lalitha/files |grep -v Created |grep -v Rejecte
d | grep -i $UserId | Mail -s "Transactions for $UserId" ***@***.com
~
Thanks,
Gundu

2

With all the following, YM,aa,MV.

If I understand your problem correctly, you are trying to find all the log entries on a given date for a given user, then send an email to someone (probably yourself) to match all the transactions except Create and Reject.

You're asking specifically about putting the "grep" pipeline in a loop. This is not an especially big problem. Do you want to loop based on entering different user names? Different dates? Both? This simplest method is something like this (using /bin/sh):

while true; do
    read UserId
    read xxx
    grep [as you originally posted it]
done

(You probably want to put your prompts in as well --- this is just to show the general method.)

Then when you've run the program and for all the dates and userids, just hit control-C to break out of the loop.

More comments follow in another post.

3

Thanks,

I like the way it is giving me option , but if the userid is not there then i need to break out saying userid doesnot exist, how to do that??

Thanks,
Gundu

4

Your 'cat * > tempfile' is a classic UUOC (useless use of cat). There's nothing wrong with making '*' (without the apostrophes so it gets expanded) the "argument" to the first command in your pipeline.

Next, when you have four greps in a pipeline, you should consider using something like awk:

awk "/$xxx/ && /$UserId/ && !/Created/ && !/Rejected/" * | Mail ...

Notice the "double quotes" around the awk script are not 'apostrophes' --- you need your variables to be expanded. Of course, If you need a "$" in your search pattern, you're in for quoting experiments ...

(Added) I forgot to mention that this search is not case-insensitive, unlike your original grep.

5

Do you mean you want to break out of the loop if there is no log entry for a given user?

6

yes, i take the user input and check to see it is there in the log file for that date and userid, if not exit with echo doesn't exist

Thanks,
Gundu

7

I'm taking this to mean there are zero lines in the resulting output. (This is a different question than whether a given userid exists.)

Okay, this is where a temporary file begins to make sense: You need the same intermediate data for two different purposes. So change it this way:

grep ... > tempfile
if [ -s tempfile ]; then
    Mail ... < tempfile
else
    echo No such userid $UserId >&2
    break
fi
rm tempfile
8

Thank you very much for timely reply. It is working

Thanks,
Gundu