Split a line on positions - Shell

Shell Programming and Scripting
1

Hi,
I want to split the length of a line based on the numbe of positions.

eg: ABCBEFGH IJKLMN asdfas

I want to split every 4 characters into a new line
Can i use cut or any easy way of using a single or 2 lines.

Thanks
Vijay

2 
> echo "ABCDEFGHIJKLMNOPQRSTUVWXYZ" | sed -e "s/..../&~/g" | tr "~" "\n"
ABCD
EFGH
IJKL
MNOP
QRST
UVWX
YZ
> echo "ABCDEFGHIJKLMNOPQRSTUVWXYZ ABC" | sed -e "s/..../&~/g" | tr "~" "\n"
ABCD
EFGH
IJKL
MNOP
QRST
UVWX
YZ A
BC
3

If you have a recent version of bash try:

string="ABCDEFGHIJKLM"
while [ ${#string} -gt 0 ]
do
      echo "${string:0:4}" #  4 characters 
      string="${string:4}" 
done
4

"recent" = any version since bash-2.0 of 1996.

In any POSIX shell:

string="ABCDEFGHIJKLM"
while [ ${#string} -ge 4 ]
do
    temp=${string#????}
    printf "%s\n" "${string%"$temp"}"
    string=$temp
done
[ -n "$string" ] && printf "%s\n" "$string"
5

Thanks all.