Shell Programming and Scripting

Hello All,

What i am doing is , i tail a file from certain chatacter and then cat -n to get the line numbers.I search for a particular string and gets it line number. What i am interested in is the next line immediately after the pattern i search.

But grep gives me result for all line statring with those digits.
For Ex:

I got the pattern in line as:

10 Pattern i searched.

Now, I need contents of line 11(i store in variable say $next_line).

so i do :

Code:

tail -c [number]  | grep "^[[:space:]]* $next_line

But it gives me result for the lines like 11, 111, 110 and so on .

Is there a way to only search for the exact number in grep.

Moderator's Comments:

Use code tags please, ty.

If I understood correct, you do not really need the line numbers but used them to identify the next line.

Maybe these examples works for you:

Code:

$> cat infile
eins
zwei
drei
vier
fuenf
$> sed -n '/drei/ {n;p;q}' infile
vier
$> awk '/drei/ {getline; print}' infile
vier

Thanks for reply.
Yes, you are right, i just track numbers to get the contents, but the thing is there are several lines in file with the same contents i grep. So i process them one by one . Also its on different boxes, i do ssh and use this. By line number i keep track which i processed and which didn't.
Will be good if i get something in grep itself or anything which allows only to search the exact number.

Ok, not sure how you correlate the stuff you get via ssh, but basically processing a file step by step should be no problem. Here is an example with awk, where the pattern is more than once in the file (if I undestood correct):

Code:

$> cat infile
1       one
2       two
3       three
4       one
5       two
6       four
7       five
8       one
9       two
10      one
$> awk '/two/ {getline; print}' infile
3       three
6       four
10      one

I added numbers so you can see that it is working on all three patterns it found which is in this case "three"

awk processes the whole file so you could put something it should do with the found patterns (ie. the following line) into the curled brackets.

Thanks a lot , it works .

Can you please explain the command ( not much familiar with awk).

Code:

/two/

match this pattern somewhere in a line; if true, execute the commands in the curled braces

Code:

getline

get the next line in the file

Code:

print

and print it

That's all.