Question

I’ve a text file with 2 million lines. Each line has some transaction information.

e.g.

23848923748, sample text, feild2 , 12/12/2008

etc

What I want to do is create a new file from a certain unique transaction number onwards. So I want to split the file at the line where this number exists.

How can I do this form the command line?

I can find the line by doing this:

cat myfile.txt | grep 23423423423

Answer 1

On a random file in my tmp directory, this is how I output everything from the line matching popd onwards in a file named tmp.sh:

tail -n+`grep -n popd tmp.sh | cut -f 1 -d:` tmp.sh

tail -n+X matches from that line number onwards; grep -n outputs lineno:filename, and cut extracts just lineno from grep.

So for your case it would be:

 tail -n+`grep -n 23423423423 myfile.txt | cut -f 1 -d:` myfile.txt

And it should indeed match from the first occurrence onwards.