Replace two blank line with a single blank line

Shell Programming and Scripting
1

Hi Guys,

I have a file in which each set of records are separated by two blank line. I want to replace it with a single blank line.

Can you guys help me out?

Regards,
Magesh

2

sed 's/ */ /g' file_name

This will replace 2 or more spaces to single space.

3

Hi Magesh!
Try 'cat -s' probably it'll solve your problem

4

Hope this helps you,

Input file:
1

2

3
4

5
6

7
8

9
10

$sed '/^$/{
N
/^\n$/s/^\n$//
}' a
1

2

3
4

5
6

7
8

9
10
5

sidorenko ur soln was simple and effective thanks...

as well as urs skmdu..

Thanks Guys

6

Or using awk

awk '!NF{getline;$0=(!NF)?$0:RS$0}1' file
7

Or using Perl:

perl -lne 'if (/^$/ and $n==0){$n++; print} elsif(!/^$/){$n=0; print} else{$n++}' filename

tyler_durden

8

GUYs one problem..
My Box is SunOS .. Whereas all the command runs fine in AIX but it throws error in SunOS (except the perl one)..

But i will really like to use the awk command or anything instead of Perl..

Could anyone gives me the command which will work in SunOS..

9

Try POSIX awk (/usr/xpg4/bin/awk) on SunOS.

10

Another awk one:

t$ cat file
record one


record two


record three

$ awk -v RS="\n\n" -v ORS="\n" 1 file
record one

record two

record three

But honestly, as already mentioned above, cat -s is easier.