Shell Programming and Scripting

Hi All,

I am karthik. I am new to this forum. I have one requirement.

I have a file with header and footer.

Header may be like

HDR0001
or
FILE20090110

(Assume it is unknown so far, but i am sure there is a header in the file)

likewise file has the trailer too.

I just want to remove the header & footer and BCP data into a table.

Note: The file size would be 1.5 GB to 2.0 GB.

So i am looking for some good way to remove the header and trailer.

Inputs are welcome!

This should do the trick:

Code:

awk 'NR<3{s=$0;next}{print s;s=$0}' file > newfile

or:

Code:

sed '1d;$d' file > newfile

Thanks Franklin!

I tested the second one. It works fine.

But i don't want to create another file. I tested the script as below

filename > filename. After executing the script, the <filename> becomes empty.

so isn't possible to remove the header & footer and store it in the same file itself?

Also can you tell me what is the difference between the first one and second one? i mean which will give give good performance?

Code:

awk 'NR<3{s=$0;next}{print s;s=$0}' file > newfile

Explanation of awk code:

Code:

NR<3{s=$0;next}

If line number < 3 assign the current line to variable s and read the next line

Code:

{print s;s=$0}

Print the previous line and assign the current line to variable s

Explanation of sed code:

Code:

sed '1d;$d'

Delete the first (1d) and the last line ($d)

Answer for one of your question:

How to make the edit in the same file itself,
use -i switch in sed as

Code:

sed -i <REQUIRED-PART>

sed: illegal option -- i
$

i got the above error message.

i am using ksh.

is there any other option to do this?

No, but you can do something like:

Code:

sed '1d;$d' file > tempfile && mv tempfile file