What if the I dont find the pattern using grep?
 

i need to search a pattern "0001p0d"
but in some of the files this pattern does not exist.
how will i know that and how can i print something like "pattern not found" instead of nothing.

Please If any one can?

Hello,

You could always easily do this by assigning a variable the output of your regex expression, regardless if you are using grep, sed, etc. Say for example:
Of course, this would have to be modified to work as advertised. I'm not using linux as we speak, so you can go ahead and fix that. And also of course, you will need to incorporate that into your script.

Cheers,

Josh

Are you just trying to find files that don't have that pattern anywhere? What is your goal here?

The OP already stated what he is trying to do. Please think before posting next time.

I did think. I read the post. It is not clear to me what the OP's real goal is. People often say one thing but mean another.

If you think it is so clear, why not try to explain it to me?

Well he is searching for this certain string within files.... And if he can not find the string, he wants to know that it was not found. Giving him the information he needs, he then can do whatever he needs to do with the code. Simple as that. He could mean anything by this, but the fact is that he wants what he asked for, and I answered his question.

And you are somehow offended that I asked for more information in order to possibly give OP a better answer? Weird.

I honestly didn't know I was offended.... :p

But it is always good to ask for more information, yes. The fact that the OP didn't say anything else, I gave him the best answer until he says otherwise.

Here you go, read this: "The OP already stated what he is trying to do. Please think before posting next time."

From the man page:

In Bash, you can check the return value by using the $? variable. For example

That's not being offended......

Anyway, before this is classified as thread jacking, what Nylex posted is also another way to do it. Multiple ways to do it....

thank you sir :)

@corp769 Sir

I am not able to use a variable in the sh script.
as soon as i run the script
it says.
var1 not found
or
error line 1 : "(" unexpected ---> although i have put both parenthesis still..

the file from which i need to search is a log file.
and the grabbed pattern gets added to a file X. So if in some files the pattern is not found then it does not print anything in the file X...making it difficult for me to identify at which point the sequence is disturbed.


so i want to print "--" instead of nothing.

If this information can help. :-\

Can you post your script for us?

cd /home/mscgnr/project
rm -rf logs

cat blank > X_RL
cat blank > Y_RL
cat blank > Z_RL
mkdir logs
cat site.txt > VSWR_LIST
mobatch /home/mscgnr/project/site.txt 'lt all;lh ru fui get vswr;rbs' /home/mscgnr/project/logs

cat site.txt > /home/mscgnr/project/logs/site1.txt

cd /home/mscgnr/project/logs
rm X_lines
rm Y_lines
rm Z_lines
sitecount=`grep -c . site1.txt`
j=1

while ( test $j -le $sitecount )
do
site=`sed -n "$j"p site1.txt`

grep "0001p0d" $site.log > X
grep "0009p0d" $site.log >> X ##-------->> here i need to add the print "not found"

## if this pattern is not found.

awk '{ if($0 ~ /[dB]/) print ; else print "--" }' X >> X_lines
#awk '{ if($0 ~ /0009p0d/) print ; else print "--" }' X >> X_lines


j=`expr $j + 1`

done