Base64 encode or decode FILE, or standard input, to standard output.

-w, --wrap=COLS

Wrap encoded lines after COLS character (default 76). Use 0 to disable line wrapping.

-d, --decode

Decode data.

-i, --ignore-garbage

When decoding, ignore non-alphabet characters.

--help

Display this help and exit.

--version

Output version information and exit.

With no FILE, or when FILE is -, read standard input.

The data are encoded as described for the base64 alphabet in RFC 3548. Decoding require compliant input by default, use --ignore-garbage to attempt to recover from non-alphabet characters (such as newlines) in the encoded stream.

info base64

should give you access to the complete manual.