Bash read & parse file - loop performance -

i'm trying read file, , parse in bash. need dd convert ebcdic ascii, loop , read x bytes, piping each x bytes row in new file:

#!/bin/bash  # $1 = input file in ebcdic # $2 = row length # $3 = output file  # convert ascii , replace nul (^@) ' ' dd conv=ascii if=$1 | sed 's/\x0/ /g' > $3.tmp file=$(cat "$3.tmp") sindex=1 findex=$2  # remove file rm $3 echo "filesize: ${#file}";     # loop, retrieving each fixed-size record , appending file while true;     # append record file     echo "${file:sindex:findex}" >> $3;      # break @ end of file     if [ $findex -ge ${#file} ]                  break;     fi      # increment index     sindex=$((sindex+findex)); done  # remove tmp rm $3.tmp 

any way make whole process faster?

answering own question. answer simple use of fold!

# $1 = ascii input file # $2 = file record length (i.e. 100) # $3 = output file (non-delimited, row-separated file)  # dd : convert ebcdic ascii # sed : replace nul (^@) space ' ' # fold : wrap input specified width (record length)  dd conv=ascii if=$1 | sed 's/\x0/ /g' | fold -$2 > $3