Convenience shell functions to tar-encrypt (and decrypt-untar) folders with gpg (default AES256)

encrypt.sh

# See also: README.
# These are convenience functions to encrypt and decrypt files and folders.

function help() {
  echo "Functions:"
  echo "  compress_folder (in_folder) [out_file_basename]"
  echo "  decompress_folder (in_file) [out_folder]"
  echo "Call with -h for help."
}

function tar_files_without_dir() {
    # Usage: tar_files_without_dir (in_folder) (out_file_basename)
    original_dir=$(pwd)
    cd "$1" || exit
    tar -czvf "/tmp/$2" ./*
    cd "$original_dir" || exit
}

# Function to compress a folder
# Usage: compress_folder (in_folder) [out_file_basename]
#     Compresses the contents of in_folder into out_file_basename.tar.gz.gpg
#     If out_file_basename is not provided, it will be the current date in YYYY-MM-DD format.
# Example: compress_folder /tmp/secret_files   ->   /tmp/secret_files-2021-01-01.tar.gz.gpg
function compress_folder() {
    # Print help
    if [ "$1" = "-h" ] || [ "$1" = "--help" ]; then
        echo "Usage: compress_folder (in_folder) [out_file_basename]"
        echo "    Compresses the contents of in_folder into out_file_basename.tar.gz.gpg"
        echo "    If out_file_basename is not provided, it will be the current date in YYYY-MM-DD format."
        echo "Example: compress_folder /tmp/secret_files   ->   /tmp/secret_files-2021-01-01.tar.gz.gpg"
        return
    fi
    # Check input
    if [ -z "$1" ]; then
        echo "Error: No input folder provided.  Call with -h for help."
        return
    else
        if [ ! -d "$1" ]; then
            echo "Error: Input folder does not exist.  Call with -h for help."
            return
        fi
    fi
    # Set output file
    if [ -z "$2" ]; then
        out_file=$(date "+%Y-%m-%d")
    else
        out_file=$2
    fi

    # Compress
    # tar -czvf /tmp/$out_file.tar.gz $1/*
    tar_files_without_dir $1 $out_file.tar.gz
    gpg -c /tmp/$out_file.tar.gz
    mv /tmp/$out_file.tar.gz.gpg .
    echo "Compressed and encrypted folder $1 into $(pwd)/$out_file.tar.gz.gpg"

    # Cleaning up
    echo "Cleaning up..."
    rm /tmp/$out_file.tar.gz
    echo "Done.  Don't forget to delete the original folder $1."
}

# Function to decompress a file
# Usage: decompress_folder (in_file) [out_folder]
#     Decompresses the contents of in_file into out_folder
#     If out_folder is not provided, it will be extracted into /tmp/{basename of in_file}/.
# Example: decompress_folder 2021-01-01.tar.gz.gpg   ->   /tmp/2021-01-01/
function decompress_folder() {
    # Print help
    if [ "$1" = "-h" ] || [ "$1" = "--help" ]; then
        echo "Usage: decompress_folder (in_file) [out_folder]"
        echo "    Decompresses the contents of in_file into out_folder"
        echo "    If out_folder is not provided, it will be extracted into /tmp/{basename of in_file}/."
        echo "Example: decompress_folder 2021-01-01.tar.gz.gpg   ->   /tmp/2021-01-01/"
        return
    fi
    # Check input
    if [ -z "$1" ]; then
        echo "Error: No input file provided.  Call with -h for help."
        return
    else
        if [ ! -f "$1" ]; then
            echo "Error: Input file does not exist.  Call with -h for help."
            return
        fi
    fi
    # Set output folder
    if [ -z "$2" ]; then
        if [[ $1 == *.tar.gz.gpg ]]; then
            out_folder=/tmp/${1%.tar.gz.gpg}/
        else
            if [[ $1 == *.gpg ]]; then
                out_folder=/tmp/${1%.gpg}/
            else
                echo "Error: Input file is not a .gpg file.  Call with -h for help."
            fi
        fi
    else
        out_folder=$2
    fi

    # Decompress
    gpg -d $1 > /tmp/$(basename $1 .gpg)
    mkdir -p $out_folder
    tar -xzvf /tmp/$(basename $1 .gpg) -C $out_folder
    echo "Decompressed and decrypted file $1 into $out_folder"

    # Cleaning up
    echo "Cleaning up..."
    rm /tmp/$(basename $1 .gpg)
    echo "Done."
}