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Adding header to an existing file

 
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# 1  
Old 07-23-2008
Adding header to an existing file
Dear All,

I need to add a header of one line to an already existing file.
I know that it can be achieved by the following:

echo "Header" > newfile
cat file1 >> newfile

But my problem is that file is huge and there is no space for creating a new file every time. Is there a way that I can add header without creating a new file?

Thanks
Shash
# 2  
Old 07-23-2008
Code:
sed -e '1i\HeaderGoesHere' originalFile > newFile

# 3  
Old 07-23-2008
Thanks for the reply sysgate. But, I don't want to create a new file.
Is there a way I can add the header in the existing file itself.

Thanks
Shash
# 4  
Old 07-23-2008
If this is something you will need to do repeatedly, I suppose you could try something with an ex script. If you had something like this in a file named addhdr:
Code:
 
1i
this is what my header will be
.
x

And you would run it like this:
Code:
 
ex - myreallybigfile < addhdr

# 5  
Old 07-24-2008
Thanks Vi-Curious!. It works for a small file. But I'm encountering an error stating Tmp file too large
while carrying out for a much bigger file.

Thanks
Shash
Last edited by shash; 07-24-2008 at 05:56 AM..
# 6  
Old 07-24-2008
Ok, so your file is too large. We need to use a "large file" safe editor. Switch from ex to ed and modify the end of the command file.

File addhdr_ed
Code:
 
1i
this is the 1st line of the header
this is the 2nd line of the header (if needed)
.
w
q

Execute as before, but using ed:
Code:
 
ed - myreallylargefile < addhdr_ed

 
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