Encrypt files easy and basic with gpg

easygpg.sh

#!/bin/bash

# Copyright © 2015 Ole Rickowski
# This work is free. You can redistribute it and/or modify it under the
# terms of the Do What The Fuck You Want To Public License, Version 2,
# as published by Sam Hocevar. See http://www.wtfpl.net/ for more details.


main(){
	# Check if target file exists
	checkfile
	
	# Perform operation
	if [ $OPERATION == "e" ]; then
		doencrypt
	else
		dodecrypt
	fi
}

usage(){
	echo "Usage: $0 <Operation> <File>"
	echo "Options:"
	echo -e "\t-e\tEncrypt file"
	echo -e "\t-d\tDecrypt file"
	echo -e "\t-f\tFile to En-/Decrypt"
	exit 1
}

# Write in variable, which operation to be performed
setoperation(){
	# If already set -> usage
	if [ $OPERATION ]; then
		echo "Only one operation can be performed!"
		usage
	fi
	OPERATION=$1
}

# Check if the file to be operated exists
checkfile(){
	# Check if given file exists
	if [ ! -f $ENCFILE ]; then
		prnt_red -e "\"$ENCFILE\" not found!\n"
		usage
	fi
}

# Encrypt the file with AES256
doencrypt(){
	#Encrypt
	gpg -q --cipher-algo AES256 --no-use-agent -c "$ENCFILE"
	#Abort if error
	if [ ! $? -eq 0 ]; then
		prnt_red "Error!"
		exit 1
	fi

	#Integrity check, if wanted
	read -p "Check integrity of encryption? [y/n]" -n 1 -r
	echo ""
	if [[ $REPLY =~ ^[YyJj]$ ]]; then
		#Decrypt again and check with original file
		gpg -q --no-use-agent -d "$ENCFILE.gpg" | cmp - "$ENCFILE" > /dev/null 2>&1
		if [ ! $? -eq 0 ]; then
			prnt_red "Integrity failed!"
		else
			prnt_green "File seems to be alright!"
		fi
	fi

	#Delete the original file if wanted
	read -p "Do you want the non encrypted file deleted? [y/n]" -n 1 -r
	echo ""
	if [[ $REPLY =~ ^[YyJj]$ ]]; then
		rm $ENCFILE
	fi
}

#Decrypt the file
dodecrypt(){
	gpg -q --no-use-agent "$ENCFILE"

	#Abort if error
	if [ ! $? -eq 0 ]; then
		prnt_red "Error!"
		exit 1
	fi

	#Delete encrypted file if wanted
	read -p "Do you want the encrypted file deleted? [y/n]" -n 1 -r
	echo ""
	if [[ $REPLY =~ ^[YyJj]$ ]]; then
		rm $ENCFILE
	fi
}

#Functions to print in color
function prnt_green(){
	echo -e "\e[1;32m$1\e[0m"
}
function prnt_red(){
	echo -e "\e[1;31m$1\e[0m"
}


# ###############################################
# Start
# Parse Arguments

# Are Arguments given?
if [ $# -eq 0 ]; then
	usage
fi

while getopts ":edf:" opt; do
	case $opt in
		e)
			setoperation e
			;;
		d)
			setoperation d
			;;
		f)
			ENCFILE=$OPTARG
			;;
		\?)
			echo "Wrong option: -$OPTARG"
			usage
			;;
		:)
			echo "Missing argument for option: -$OPTARG"
			usage
			;;
	esac
done

main