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Unix help to find blank lines in a file and print numbers on that line


 
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# 1  
Old 10-09-2009
Unix help to find blank lines in a file and print numbers on that line

Hi,
I would like to know how to solve one of my problems using expert unix commands.

I have a file with occasional blank lines;
for example;

dertu
frthu
fghtu

frtty
frtgy
frgtui

frgtu
ghrye
frhutp
frjuf

I need to edit the file so that the file looks like this;
1
dertu
frthu
fghtu
2
frtty
frtgy
frgtui
3
frgtu
ghrye
frhutp
frjuf
************
That is: I want to grep or find the blank line and sequentially number the blank lines and print that number in the blank space.

Hope you guys understood what I wanted.

Please let me know the best way for doing this;

Lucky Ali
# 2  
Old 10-09-2009
Hi.

Code:
awk '
/^$/ { print ++C; next} 1
' input_file


Last edited by Scott; 10-09-2009 at 05:19 PM.. Reason: removed statement "If I understand you correctly:" as even for me it was quite understandable!
# 3  
Old 10-09-2009
Thank you very much
It worked perfectly
Lucky Ali
# 4  
Old 10-09-2009
Shorter Smilie
Code:
awk '$0=($0)?$0:++c' file

# 5  
Old 10-09-2009
I'm not one to use things like LOL, LMAO, etc. But just for you:

ROFL!!!!

And it's only shorter because you didn't use spaces and your filename was shorter :-)

Shorter:
Code:
awk '$0=($0)?$0:++c' f


Last edited by Scott; 10-09-2009 at 05:47 PM.. Reason: Changed grammatical error "one one" to "not one", thus changing one one to not
# 6  
Old 10-09-2009
Quote:
Originally Posted by scottn
Code:
awk '
/^$/ { print ++C; next} 1
' input_file

Thank you.
Your solution simplified
Code:
awk '!NF{$0=++c}1' file

There is always more than one way to solve a problem Smilie
# 7  
Old 10-09-2009
And that's the beauty of it.

There's a lot to be said for the "concise but readable" option though.

When you can buy a 1.5 TB disk for 139 Swiss Francs, where's the harm in adding some white-space?!

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