6

i have been using xxd to create a hexa representation of a file(any file like .jpg, .docx, .zip etc), like this,.. 

$ xxd -p original_file.zip > hexa_format.txt

and to reverse 

$ xxd -r -p hexa_format.txt > original_file.zip

if anybody feels that this isn't the proper way, please correct me. anyhow this isn't my question. now i have to convert them to binary instead of hexa. so the command goes like this, if im correct.

$ xxd -p -b original_file.zip > binary_format.txt

my question is,
how do i reverse it back to the original file from the binary file(binary_format.txt) created from the above command. the man page of xxd says it cannot be done(in the last line).

-b | -bits
              Switch to bits (binary digits) dump, rather than hexdump.   This
              option  writes octets as eight digits "1"s and "0"s instead of a
              normal hexadecimal dump. Each line is preceded by a line  number
              in  hexadecimal and followed by an ascii (or ebcdic) representa‐
              tion. The command line switches -r, -p, -i do not work with this
              mode.

if this couldn't be done is there any other command that can do it,. like piping multiple comamnds so.

arvindh
  • 163

2 Answers2

1

You will have to write your own binary to hex function ...

cut -f2-8 -d' ' infile | tr -d '\n' | tr ' ' '\n' | while read l; 
do 
  echo -n    $(bin_to_hex($l)) >> outfile
  (( ++n )) 
  (( n % 60 == 0)) && echo  "" >> outfile 
done

This should output the same format as -p which can then be run through -r. If you read the man page for xxd you will read that there is no -r for -b. It says so on the excerpt that you included in your question.

Allen
  • 156
  • 6
0

You alter the structure of the file do you can't easy do this. Maybe something like this can help (but you will loose newline characters:

awk '{printf $8}' binary_format.txt >out_file
Romeo Ninov
  • 7,848