How do I create a new line after every 3 characters in a text file?

If I had a .txt file that has one line as

abcdefghijklmnopqrstuvwxyz

I would like either to change or create a new .txt file that would look like this:

abc

def

ghi

jkl

mno

pqr

stu

vwx

yz

So, it's essentially reading 3 characters from the right, creating a new line '\n', going to the second line, reading 3 characters, creating a new line, etc.

Thank you!

Answer 1

[ES]

fileID=fopen('InputFile.txt','r');
AllText = fscanf(fileID, '%s')
TextLength=length(AllText);
NoOfLines=ceil(TextLength/3);
OutFileID=fopen('OutputFile.txt','w');

for l1=0:NoOfLines
    try
        SrcString=AllText((l1*3)+1:(l1*3)+3)
    catch
        SrcString=AllText((l1*3)+1:end)
    end
    fprintf(OutFileID,'%s\r\n',SrcString);
end