Android <-> PC notepad style file editor/sync

Wed, 30 Apr 2025 00:00:00 +0000

General info

Mobile and PC can be in any different networks, ssh is used for comms. OpenVPN is used for handy and secure access bridging any networks.

Android setup

install “Simple SSHD” from play market, it is dropbear sshd daemon
- inject your public key into phone sshd
- configure port etc
- create sshd shortcut on home screen
install fossify notepad from play market
- configure new txt file with export to sd option
- make the file /sdcard/000notepad.txt

Linux setup

working ssh client and some network required
openvpn client is required

Place editor script into PC ~/bin/memo

#!/bin/bash
MNT=$(mktemp -d); sshfs phone:/sdcard/ $MNT && vi $MNT/000notepad.txt && umount $MNT && rmdir $MNT

SSH client config setup with LAN/VPN aliasing

# phone in VPN network
Match originalhost op10 localnetwork 172.16.10.0/24
Hostname 172.16.10.2

# phone in home LAN
Host op10
HostName 192.168.1.44
Port 2222

Usage

Run memo command in any network while phone sshd is running and you can view/edit the file from anywhere

OpenVPN networking

Thu, 03 Apr 2025 00:00:00 +0000

Package setup for building files at any host computer

sudo apt install easy-rsa openssl openvpn

Package setup for OpenVPN server

sudo apt install openvpn

Create directory for building and keeping keyfiles

mkdir ~/vpn_repo
cd ~/vpn_repo

* From here on, everything happens at ~/vpn_repo !!! *

Fetch & prepare easy-tls

wget https://raw.githubusercontent.com/TinCanTech/easy-tls/refs/heads/master/easytls
chmod 750 easytls

For creating all the needed OpenVPN server files

cat >server.sh

#!/bin/bash

# cert & ca expiry 10 years
export EASYRSA_KEY_SIZE=2048
export EASYRSA_CA_EXPIRE=3650
export EASYRSA_CERT_EXPIRE=3650

TARGET=$1
USER=$2
PASS=$3

if [ -z $TARGET ]
then
 echo "Give servername as arg"
 exit
fi

make-cadir $TARGET
if [ $? -eq 0 ]
 then
 cd $TARGET

 # build server cert package
 ./easyrsa init-pki
 echo $TARGET | ./easyrsa build-ca nopass
 ./easyrsa gen-dh
 echo yes | ./easyrsa build-server-full $TARGET nopass

 # prepare tls-auth key
 if [[ ! -d pki/easytls ]]
 then
 ../easytls init-tls
 ../easytls build-tls-auth
 fi

 cd ..
 mkdir -p out
 # symlink all files needed on server side
 ln -srf $TARGET/pki/private/$TARGET.key out/
 ln -srf $TARGET/pki/ca.crt out/${TARGET}_ca.crt
 ln -srf $TARGET/pki/easytls/tls-auth.key out/${TARGET}_tls-auth.key
 ln -srf $TARGET/pki/dh.pem out/${TARGET}_dh.pem
 ln -srf $TARGET/pki/issued/$TARGET.crt out/

 echo "#### OpenVPN server files"
 find out | tail +2
 echo "####"
 echo "Copy these files to server /etc/openvpn/server/"
fi

For creating client profiles

cat >gen_user.sh

Openvpn on Terminal