Fix Gpg Decrypt Error : Inappropriate ioctl for device

The Error

When you try to decrypt something using gpg and if gpg is reading the input from a pipe, like this echo "something encrypted" | gpg --decrypt, it fails with the following error

gpg: public key decryption failed: Inappropriate ioctl for device
gpg: decryption failed: Inappropriate ioctl for device

The solution

This happens because GPG does not know where to read the input from, simply set the env variable GPG_TTY.

export GPG_TTY=$(tty)