how to insert a newline \n after x numbers of words, with AWK or Sed

Question

I have this in one line:

We were born in the earth beyond the land

I want it in 3 words lines, to be like this:

We were born
in the earth 
beyond the land

Answer 1

$ xargs -n3 < file
We were born
in the earth
beyond the land

$ egrep -o '\S+\s+\S+\s+\S+' file 
We were born
in the earth
beyond the land

Answer 2

Using awk :

awk '{ 
    for ( i = 1; i <= NF; i++ ) { 
        printf "%s%c", $i, (i % 3 == 0) ? ORS : OFS 
    } 
}' infile

It yields:

We were born
in the earth
beyond the land

Answer 3

With GNU sed:

sed 's/\(\w\w*\W*\w\w*\W*\w\w*\W*\)/\1\n/g' input

and short version:

sed 's/\(\(\w\w*\W*\)\{3\}\)/\1\n/g' input

Answer 4

Here's one sed solution:

sed -e 's/\s/\n/3;s/\s/\n/6;s/\s/\n/9'

It replaces the third, sixth and ninth spaces with newlines.

This one will handle longer lines, even if they aren't multiples of three words:

sed -e 's/\(\(\S\{1,\}\s*\)\{3\}\)/\1\n/g'

Answer 5

任何有awk和sed的系统几乎肯定都会有Perl：

 cat myfile.txt | perl -lane 'while(($a,$b,$c) = splice(@F,0,3)){print "$a $b $c"}'