Shell Programming and Scripting

awk -F"," 'BEGIN{c=3} {for (i=1;i<=NF;i++) { printf i%c ? i!=NF ? $i FS : $i"\n" :  $i"\n"}}' filename

tr , '\n' < file | paste -d, - - -

#!/usr/bin/perl

use warnings;
use strict;

my @result;
my $i;
my $line;
my $cols;

## Usage: command [number of columns]
if ( ! $ARGV[0] ) {
    $cols = 3;     # defaults to 3 columns if none given
} else {
    $cols = $ARGV[0];
}

my $infil = "new_num.txt";
my $outfil = "result.txt";
open ( my $fin, '<', "$infil" ) or die "Cannot read the file $infil: $!\n";
open ( my $fout, '>', "$outfil" ) or die "Cannot read the file $outfil: $!\n";

#START:
while ( $line = <$fin> ) {
    chomp ( $line );
    @result = split (",", $line);
    my $sz = $#result;
    foreach (@result) {
        $i += 1;
        print ($_);
        print $fout ($_);
        if ( $i % $cols != 0 ) {
            print (",") if not ( $i > $sz );
            print $fout (",") if not ( $i > $sz );
        }else{
            print ("\n");
            print $fout ("\n");
        }
    }
    if ( $i % $cols ) {
        print ("\n");
        print $fout ("\n");
    }
    $i = 0;
}
close $fout;
close $fin;

#  output
# (3 cols)
# ~~~~~~
# 1,2,3
# 4,5,6
# 7,8,9

# (multi-line)
# ~~~~~~
# a,b,c
# d,e,f
# g,h,i
# j,k,l
# m,n,o
# p,q,r
# s,t,u
# v,w,x
# y,z
# 0,1,2
# 3,4,5
# 6,7,8
# 9
# A,B,C
# D,E,F

a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z
0,1,2,3,4,5,6,7,8,9
A,B,C,D,E,F

a,b,c,d,e,f
g,h,i,j,k,l
m,n,o,p,q,r
s,t,u,v,w,x
y,z
0,1,2,3,4,5
6,7,8,9
A,B,C,D,E,F

#!/bin/ksh
FieldsPerLine=${1:-3}			# Set the number of fields to be placed
					# on each output line with a default of
					# 3 if no operands are given.
awk -F, -v fpl="$FieldsPerLine" '	# Set input field separator to comma and
					# set "fpl" to the number of fields to put
					# on each output line.
{	for(i=1;i<=NF;i++){		# For each input field...
		S=((S!="")?S OFS $i:$i)	# If string "S" is not an empty string,
					# set string "S" to the current 
					# contents of "S" followed by the 
					# output field separator followed by the
					# contents of the current field; 
					# otherwise, set string "S" to the 
					# contents of the current field.
		if(i%fpl==0){		# If the current field # is evenly
					# divisible by the specified number of
					# fields per output line...
			print S;S=""	# Print the current contents of the
					# string "S" and clear the contents of
					# "S".
		}
	}
	if(NF%fpl){			# If the number of fields on this input
					# line is not evenly divisible by the
					# specified of fields per output line...
		print S;S=""		# Print the remaining fields for this
					# line and clear the contents of "S".
	}
}' OFS=, Input_file			# Set output field separator to comma
					# and specify the input file to be
					# processed.

a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z
0,1,2,3,4,5,6,7,8,9
A,B,C,D,E,F

a,b,c
d,e,f
g,h,i
j,k,l
m,n,o
p,q,r
s,t,u
v,w,x
y,z
0,1,2
3,4,5
6,7,8
9
A,B,C
D,E,F

a,b,c,d,e
f,g,h,i,j
k,l,m,n,o
p,q,r,s,t
u,v,w,x,y
z
0,1,2,3,4
5,6,7,8,9
A,B,C,D,E
F