macOS Command Line Zip script using 7z with max compression, AES-256, header encryption & PW Protection, also splitting zip into 500MB volumes

secure_zip_split.sh

#!/bin/bash

# Secure Encrypt Script using 7z and splitting zip into 500MB volumes
# Requires: 7z (7-Zip) is not installed. Download it from 7-zip.org

# Exit on any error
set -euo pipefail

# Specify the folder location of the 7zip executable file
ZIPLOCATION=$HOME"/Downloads/7Zip"

# Check if 7z is installed
if ! command -v $ZIPLOCATION/7zz &> /dev/null; then
    echo "❌ 7z (7-Zip) is not installed. Download it from 7-zip.org"
    exit 1
fi

# Check for correct usage
if [ $# -lt 2 ]; then
	echo "❌ No paramaters specified"
	echo "Usage: $0 <output_name.7z> <source_file_or_folder> [<optional_source_file_or_folder>]"
	echo "Note:  Will split zip into 500M volumes"
    exit 1
fi

COUNTER=0
OUTPUT="$1"
FILESNOTEXIST=0

# Prompt for password (secure input)
read -rsp "Enter password: " PASSWORD
echo
read -rsp "Confirm password: " PASSWORD_CONFIRM
echo

if [ "$PASSWORD" != "$PASSWORD_CONFIRM" ]; then
    echo "❌ Passwords do not match!"
    exit 1
fi

# Check if source exists
for SINGLEFILE in "$@"
do
	COUNTER=$((COUNTER + 1))
	if [ $COUNTER -gt 1 ]; then
		# Check if source exists
		if [ ! -e "$SINGLEFILE" ]; then
			echo "Source '$SINGLEFILE' does not exist."
			FILESNOTEXIST=1
		fi
	fi
done

# Exit if one or more source files do not exist
if [ 1 -eq "$FILESNOTEXIST" ]; then
	echo "❌ One of more source files do not exist."
	exit 1
fi

# Prevent overwriting existing archive
if [ -e "$OUTPUT" ]; then
    echo "⚠️ Output file '$OUTPUT' already exists. Append to existing file? (Y/N): "
    read -r CONFIRM
    if [[ ! "$CONFIRM" =~ ^[Yy]$ ]]; then
    	echo "❌ Aborted to prevent overwrite."
        exit 1
    fi
fi

# Run the 7z command with max compression, AES-256, and header encryption & PW Protection & volume splitting
$ZIPLOCATION/7zz a -x\!".DS_Store" -r0 -t7z -mx=9 -m0=lzma2 -mhe=on -v500m -p"$PASSWORD" "$@"

# Clear password variables from memory
unset PASSWORD
unset PASSWORD_CONFIRM

echo "✅ Encrypted archive created: $OUTPUT"