How to convert a text file to binary file using linux commands

Question

I have hex code of a binary in text (string) format. How do I convert it to a binary file using linux commands like cat and echo ?

I know command following command with create a binary test.bin. But what if this hexcode is in another .txt file ? How do I "cat" the content of text file to "echo" and generate a binary file ?

# echo -e "\x00\x001" > test.bin

Solution

use xxd -r. it reverts a hexdump to its binary representation.

source and source

Edit: The -p parameter is also very useful. It accepts "plain" hexadecimal values, but ignores whitespace and line changes.

So, if you have a plain text dump like this:

echo "0000 4865 6c6c 6f20 776f 726c 6421 0000" > text_dump

You can convert it to binary with:

xxd -r -p text_dump > binary_dump

And then get useful output with something like:

xxd binary_dump

Comments

[szotsaki]

In a one liner: xxd -r -p <(echo "0A 04 00 00 34") | xxd

[Jacqueline P.]

does not work on my linux guess need to install dependencies

[daouzli]

@JacquelineP. what dependencies ? It is a C++11 open source program so it depends of course on a compiler as g++ but there is no exotic library. Only standard libraries are used (as I remember regex is std).

[Elly Ambet]

And how do I reverse the above action? as in: xxd -r -p text_dump > binary_dump gives me a file(binary_dump). How do I revert the action of converting the binary_dump to text_dump??

[1010]

@EllyAmbet you can use xxd -p binary_dump > text