Need UNIX Shell script

Question

My file(xxx.mf) contains big single line which includes header,details,tailer and number of records.
example
RA.........RW...RS.....RW....RS.....RW...RS..RT...39214
This RA......... header record(1024 bytes)
RW...RS.....RW....RS.....RW...RS..(38MB approximately)
RT...Tailer record(1024 bytes)
39214 number of records.
User needs as
RA......
RW..
RS...
RW..
RS...
RW..
RS..
RT.....
39214
I need shell script to get above result. Please help me regarding this.

Answer 1

trivial ksh shell script to insert linefeed characters in file
#!/bin/ksh
# copy input file and insert linefeed characters in output file
# parse string and insert linefeed after each fixed-length record
# input file: testin.txt
# contains 10 5 character records in one string
# R0001R0002R0003R0004R0005R0006R0007R0008R0009R0010
# output file: testout.txt
# contains 10 records separated by linefeed
# R0001
# R0002
# R0003
# R0004
# R0005
# R0006
# R0007
# R0008
# R0009
# R0010
# arguments:
# $1 input filename
# $2 output filename
str=`cat $1`
rec_len=5
str_len=$((`expr length ${str}`))
rec_cnt=$((${str_len}/${rec_len}))
i=1
while (( i <= $str_len ))
do
rec_out=`expr substr $str $i $rec_len`
echo ${rec_out} >> $2
(( i += $rec_len ))
done