regex to delete multiple blank lines in a file?

fedora · #1 (**permalink**) 10-11-2007

can't figure out a way to delete multiple empty lines but keep single empty lines in a file, file is like this
#cat file
1

2

3

4

5
6
-

What I want is
1

2

3

4

5
6
--

any idea?

vgersh99 · #2 (**permalink**) 10-11-2007

Code:

sed '/^$/d;G' myFile

fedora · #3 (**permalink**) 10-11-2007

thanks for the answer, but by doing this, you also ADD a empty line between
5 and 6, which before has no empty line between.

5
6

not
5

6

Quote:

Originally Posted by vgersh99

Code:

sed '/^$/d;G' myFile

radoulov · #4 (**permalink**) 10-11-2007

Code:

awk 1 RS= ORS="\n\n" filename

Use nawk or /usr/xpg4/bin/awk on Solaris.

fedora · #5 (**permalink**) 10-11-2007

Tjhis is awesome!

Can you explain a little bit what the argument "1" does here?

Quote:

Originally Posted by radoulov

Code:

awk 1 RS= ORS="\n\n" filename

Use nawk or /usr/xpg4/bin/awk on Solaris.

radoulov · #6 (**permalink**) 10-11-2007

Sure:

everything <>0 in awk is true (you can use whatever you want: 1,2 ... 42 ...), true means use default action, which is print the current record.

You could use this, if you prefer:

Code:

awk -- -42 RS= ORS="\n\n" filename

fedora · #7 (**permalink**) 10-11-2007

Thanks again!

Quote:

Originally Posted by radoulov

Sure:

everything <>0 in awk is true (you can use whatever you want: 1,2 ... 42 ...), true means use default action, which is print the current record.

You could use this, if you prefer:

Code:

awk -- -42 RS= ORS="\n\n" filename

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