the issue is i have .txt file with passwords and other sensitive data

I need to store this file updated! at at least 2 locations - My home computer (Windows) as a source and external computer (Linux) as a backup.
Condition is that data must be encrypted on the linux box

I want to ask which tool/method i need to use for this purpose?

The way is store encrypted text there: https://www.protectedtext.com but it is not compatible for automated backing up. (what if that service went offline, and i dotn want to waste time doing manual backups of that)

Related topic: http://internetlifeforum.com/computers-technology/1364-how-encrypt-sync-data-intostorage-like-dropbox-gdrive/