How can some binary expressed in ASCII 0s and 1s be converted to a binary file?

Question

I've got a PDF expressed as an ASCII file of 0s and 1s, produced in the following way:

filepath="Manna.pdf"
data="$((echo obase=2; hexdump -ve'/1 "%u\n"' "${filepath}") | bc | xargs printf %08i)"
inputText="$(echo "${inputText}" | sed 's/\(.*\)/\L\1/')"
echo "${data}" > Manna.txt

How can this be converted back to PDF?

why don't use base64? not only it's a lot shorter, it's easier to encode and decode — phuclv, Sep 10 '19 at 13:24
@phuclv Ha, in this case it was to be able to communicate using light with a secure, air-gapped computer! — BlandCorporation, Sep 10 '19 at 14:41

score 1 · Accepted Answer · answered Sep 10 '19 at 13:55

1

I don't know why you'd want to do that, but perhaps you could use Perl's oct to convert each 8-bit binary substring into its numeric value and print that as a char:

perl -pe 's/([01]{8})/sprintf "%c", oct("0b$1")/ge'

Ex.

$ printf 'foo bar\nbaz\n' | 
    { echo obase=2; hexdump -ve'/1 "%u\n"' ; } | bc | xargs printf %08i | 
    perl -pe 's/([01]{8})/sprintf "%c", oct("0b$1")/ge'
foo bar
baz

answered Sep 10 '19 at 13:55

steeldriver

143,099

Magic, thanks for your help on that! cat "${filein}" | perl -pe 's/([01]{8})/sprintf "%c", oct("0b$1")/ge' > "${fileout}" does the trick. :) – BlandCorporation Sep 10 '19 at 15:03

How can some binary expressed in ASCII 0s and 1s be converted to a binary file?

1 Answers1