Quick 7z based directory locking script. I created this because I want an easy way to quickly encrypt and decrypt a directory.

locker.sh

#!/bin/bash

USAGE_TEXT="Usage: locker.sh <command> target

Commands:

    lock        Expects target to be a directory. This directory will be compressed
                with a password using 7z removing the original directory afterwards.

    unlock      Expects target to be a 7z compressed file. Unlocks the given
                directory using 7z removing the original compressed file afterwards.

    help        Display this help text.
"

COMMAND=$1
TARGET=${2%/} # Remove trailing /

throw_error () {
    echo "ERROR: $1" > /dev/stderr
    exit 1
}

throw_user_error () {
        echo "ERROR: $1" > /dev/stderr
        echo "$USAGE_TEXT"
        exit 1
}

check_target_type () {
    if [[ -z "$2" ]]; then
        throw_user_error "Missing target as second parameter."
    elif [[ "$1" = "lock" && ! -d "$2" ]]; then
        throw_user_error "Target must be a directory."
    elif [[ "$1" = "unlock" && ! -f "$2" ]]; then
        throw_user_error "Target must be a file."
    fi
}

shred_files () {
    if [[ -d "$1" ]]; then
        echo "Shredding old directory after encryption.."
        find "$1" -type f -exec shred -uz {} +
        rm -r "$1"
    elif [[ -f "$1" ]]; then
        echo "Shredding old file after decryption.."
        shred -uz "$1"
    fi
}

if [[ "$COMMAND" = "lock" ]]; then
    check_target_type "$COMMAND" "$TARGET"
    if 7z a -p -mhe -t7z "$TARGET" "$TARGET"; then
        shred_files "$TARGET"
    else
        throw_error "Lock failed!"
    fi
elif [[ "$COMMAND" = "unlock" ]]; then
    check_target_type "$COMMAND" "$TARGET"
    if 7z x "$TARGET"; then
        shred_files "$TARGET"
    else
        throw_error "Unlock failed!"
    fi
elif [[ "$COMMAND" = "-h" || "$COMMAND" = "--help" || "$COMMAND" = "help" ]]; then
    echo "$USAGE_TEXT"
else
    throw_user_error "Missing or invalid command."
fi

exit 0