How do I dump raw binary 'bits' from a file, without line numbers and ASCII interpretation?

Question

How do I dump a "pure" and plain binary sequence of bits?

For example, I have this:

 0000000: 10001001 01010000 01001110 01000111 00001101 00001010  .PNG..
 0000006: 00011010 00001010 00000000 00000000 00000000 00001101  ......
 000000c: 01001001 01001000 01000100 01010010 00000000 00000000  IHDR..
 0000012: 00000010 01011000 00000000 00000000 00000001 10010000  .X....
 0000018: 00001000 00000010 00000000 00000000 00000000 11111101  ......
 000001e: 01010111 10001001 11001111 00000000 00000000 00000000  W.....
 0000024: 00000111 01110100 01001001 01001101 01000101 00000111  .tIME. 

Those line numbers on the left, and the ASCII on the right is a problem for me. I did try this to remove it:

xxd -b /root/Desktop/image.png | sed -r "s/\d32{3,}.*//g" | sed "s/.*://" | sed "s/\d32//g"

However, I did not succeed:

 100010010101000001001110010001110000110100001010.PNG..
 000110100000101000000000000000000000000000001101......
 010010010100100001000100010100100000000000000000IHDR..
 000000100101100000000000000000000000000110010000.X....
 000010000000001000000000000000000000000011111101......
 010101111000100111001111000000000000000000000000W.....
 000001110111010001001001010011010100010100000111.tIME.

Is there a tool like 'xxd' or 'hexdump' or something that could produce a clean binary sequence out of a file?

For example,

 01010101000100100100010100100010000010101010101010101001011
 10101010101010100100101010101010100000010001000100001000000

Solution

It's simple enough to parse the output into the format you want:

xxd -b /root/Desktop/image.png | cut -d: -f 2 | sed 's/  .*//; s/ //g'

The cut will remove the line numbers and the sed will first remove the last column (s/ .*// will remove everything that comes after two consecutive spaces) and then removes all single spaces.

You could also use awk:

xxd -b ~/a.png | awk '{print $2$3$4$5$6$7}'

Or Perl:

xxd -b ~/a.png | head -1 | perl -lane 'print join "",@F[1..6]'

Or coreutils:

xxd -b ~/a.png | cut -d" " -f2-7 | tr -d ' '

Comments

[terdon]

On what operating system? It looks like you're running some kind of *nix but which one? Is it Linux? UNIX? OSX? Something else?

[learnerX]

@terdon Linux (Debian 7)

[Peter Mortensen]

One would think the -p would work for leaving out line numbers and ASCII, but it only works for hexadecimal output, not binary (as noted on the man page: The command line switches -r, -p, -i do not work with this mode.).

[learnerX]

Awesome, that did it. I keep telling myself to learn 'awk' and 'sed' but somehow I just never did. I will start learning it soon.