CODEWITHSUNDEEP
sedawk
user294280
user294280

Reputation: 361

sed/awk to double space file

I have a file with blank lines and I need to double space the lines in the file. Meaning I need a blank line between two lines with text in it. Can you show me an easy way to do it with awk and/or sed

Upvotes: 5

Views: 6021

Answers (10)

kvantour
kvantour

Reputation: 26481

A very quick way using 

sed '/^$/d;G'

This deletes all empty lines using the command /^$/d and appends the content of the hold space (which is empty) to the pattern space with a newline in between (G).

A very quick way is using 

awk 'BEGIN{RS="";FS="\n";ORS=OFS="\n\n"}{$1=$1}1'

How does this work:

knowns the concept records (which is by default lines) and you can define a record by its record separator RS. If you set the value of RS to an empty string, it will match any multitude of empty lines as a record separator. The value ORS is the output record separator. It states which separator should be printed between two consecutive records. This is set to two <newline> characters. This, however, does not solve the problem when you have a multi-line record. So for this, we define fields (by default words). The field separator FS is defined as a single <newline> character such that each field represents a line. And the output field-separator is defined as two <newline> characters. We convert FS into OFS by reassigning the first field to itself {$1=$1} Finally, the statement 1 is a shorthand for {print $0} which prints the current record followed by the output record-separator ORS.

Upvotes: 1

Bor
Bor

Reputation: 793

With awk: 

 # double space a file
 $ awk '1;{print ""}' file

Another way

 # or like this
 $ awk 'BEGIN{ORS="\n\n"};1' file

Awk one-liners

Upvotes: 0

Vikki
Vikki

Reputation: 49

Assuming:

  1. You want to do this in just SED
  2. You want to do it all in one pass
  3. Some of your "blank" lines might contain tabs|spaces
  4. The current spacing is non-uniform (0, 1, or more blanks after each line)
  5. You want to end up with uniform double-spacing

Try this:

#!/bin/sed -f
/^[ \t]*$/d
/^..*$/a\

The first line says:       If you see a "blank line", delete it.
The second line says: If you see a non-blank line, append a line after it.

Upvotes: 4

Sabarish
Sabarish

Reputation: 23

sed -n 's/.*/&\n/p'

& and \n should work I guess

Upvotes: 0

kev
kev

Reputation: 161754

using sed

$ sed G input.txt | cat -s

Upvotes: 7

Vikki
Vikki

Reputation: 49

Assuming:

  1. You want to do this in just AWK
  2. You want to do it all in one pass
  3. Some of your "blank" lines might contain tabs|spaces
  4. The current spacing is non-uniform (0, 1, or more blanks after each line)
  5. You want to end up with uniform double-spacing

Try this:

awk '$0 !~ /^[ \t]*$/ { print $0, "\n" }' <file>

Breaking this up,

  The part before the curly bracket says:   Match only non-blank lines
  The part within the curly brackets says:   Print this line and append one more (a blank one)

Upvotes: 0

glenn jackman
glenn jackman

Reputation: 246877

Assuming you want to keep the existing blank lines intact:

awk '
    prev && $0 {print ""}
    {print; prev = $0}
'

The first test will only be true if both the previous line and the current line are non-empty.

Upvotes: 0

jcomeau_ictx
jcomeau_ictx

Reputation: 38462

jcomeau@intrepid:/tmp$ cat test.txt
test
tset 2
test 3
test 4
jcomeau@intrepid:/tmp$ sed 's/\(.*\)/\1\n/' test.txt
test

tset 2

test 3

test 4

Sai's sed G test.txt works also, but I have no idea how.

Upvotes: 0

Alex Gitelman
Alex Gitelman

Reputation: 24722

Try this 

awk '{print $0 "\n"}' fileName

Upvotes: 0

Sai
Sai

Reputation: 3957

Try this

sed '/^$/d' fileName | sed G

Upvotes: 11

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