using bash: write bit representation of integer to file

Question

I have a file with binary data and I need to replace a few bytes in a certain position. I\'ve come up with the following to direct bash to the offset and show me that it fou

Answer 1

printf is more portable than echo. This function takes a decimal integer and outputs a byte with that value:

echobyte () {
    if (( $1 >= 0 && $1 <= 255 ))
    then
        printf "\\x$(printf "%x" $1)"
    else
        printf "Invalid value\n" >&2
        return 1
    fi
}

$ echobyte 97
a
$ for i in {0..15}; do echobyte $i; done | hd
00000000  00 01 02 03 04 05 06 07  08 09 0a 0b 0c 0d 0e 0f  |................|
00000010