Is there a binary-safe “triple less than” <<< operator in bash?

Question

This is a rather hypothetical question, so please don't ask me why I'd want to do this.

Assuming that I have a variable GIF that contains binary data, and assuming that I cannot use the pipe | operator, the following should be the correct way to use 'triple-less-than' operator:

openssl enc -base64 <<< $GIF

However, it appears to me that <<< is not binary-safe and therefore the binary data gets corrupt.

Is there a binary-safe equivalent?

Answer 1

The here string redirection (<<<) is a simple form of here document redirection (<<). Here string redirection is not "binary safe"; Bash will perform expansion on the here string. In addition, Bash will append a new-line to the end of the here string (issue the command xxd -p <<< "foo" and you'll get 666f6f0a in return).

Your only safe bet, excluding pipes, is I/O redirection.

Answer 2

Bash isn't binary safe in general, and will corrupt nulls and newlines in variables containing binary content during substitution.

So I think the answer is "no" but more fundamentally "not in a shell scripting language" because they all seem to have problems with binary.

I'd say however you plan to get the data into $GIF, you instead get it into a file, or use python as an alternative scripting language which will handle binary data without problems.