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How to remove blank lines

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# 1  
Old 05-25-2011
How to remove blank lines
Hi,
I am facing a problem related to removing blank lines from a text document.

Code:
 Input
Error    17-05-2011 11:01:15    VisualSVN Server 2.1   1001    
 
The following information was included with the event:  
 
line3

line4 
  
Error    17-05-2011 11:00:25    VisualSVN Server 2.1    1001    
 
The following information was included with the event:  
 
line3

line4

Expected Output
Code:
Error    17-05-2011 11:01:15    VisualSVN Server 2.1    1001     
The following information was included with the event:  
line3line4 
  
Error    17-05-2011 11:00:25    VisualSVN Server 2.1    1001     
The following information was included with the event:  
line3line4

I tried using
Code:
 sed '/^$/d' filename

but to no avail.

Regards,
Mayur
# 2  
Old 05-25-2011
Code:
 
grep "." filename

# 3  
Old 05-25-2011
Code:
cat temp.txt | sed   /'^$'/d

Code:
cat temp.txt | grep -v  '^$'

# 4  
Old 05-25-2011
Quote:
Originally Posted by palanisvr
Code:
cat temp.txt | sed   /'^$'/d

Code:
cat temp.txt | grep -v  '^$'

This is Useless Use of Cat.
# 5  
Old 05-25-2011
Hi,
Thanks for your quick replies. But the solution you mentioned is not working also the file size is huge but i don't think it will have greater impact. The solution gives me the output as below
Code:
The following information was included with the event: 

line3
line4
 
Error   17-05-2011 11:00:25     VisualSVN Server 2.1    1001

The following information was included with the event: 

line3
line4

But my desired output is a little different from given above.
# 6  
Old 05-25-2011
Quote:
Originally Posted by mayursingru
I tried using
Code:
 sed '/^$/d' filename

but to no avail.

Regards,
Mayur
It might be that "empty" lines are not completely empty but filled with spaces (or other non-printable characters). Try the following:

Code:
sed '/^[<blank><tab>]*$/d' /path/to/input > /path/to/output

Replace "<blank>" and "<tab>" with literal blank/tabulator characters.

Still, the way you presented your expected output was a bit different: you wanted to retain a blank line before every paragraph starting with "Error". To accomplish this try:

Code:
sed '/^[<blank><tab>]*$/d
     /^Error.*$/ s/^/^M/' /path/to/input > /path/to/output

The "^M" is a literal newline. You get it (in vi) by switching to insert-mode, pressing CRTL-V and then ENTER.

I hope this helps.

bakunin
# 7  
Old 05-25-2011
As bakunin mentioned, it seems there are many lines that seem to be empty but consist of spaces.

Code:
$> cat ./mach.ksh
awk '
        /^Error/ {print l?l RS RS $0: RS $0; l=x; next}
        /^line/ {l=sprintf("%s%s", l, $0); next}
        /^[[:space:]]*$/ {next}
        {print}
        END{
                if(l){print l}
        }
' infile
$> ./mach.ksh

Error    17-05-2011 11:01:15    VisualSVN Server 2.1   1001
The following information was included with the event:
line3line4

Error    17-05-2011 11:00:25    VisualSVN Server 2.1    1001
The following information was included with the event:
line3line4
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