Manage a plain-text to-do list from the command line.
Free and open source (GPL-3.0 licence per GitHub).

Notes, tasks & docs
Manage tasks, priorities and recurring work from the terminal.
Manage tasks, priorities and recurring work from the terminal.
Individual task capture, prioritisation, projects and recurring work for people comfortable in a terminal. Not a native mobile, graphical or managed team service. For Any.do and TickTick: capture, prioritise and complete personal tasks, organise projects and repeat scheduled work in a free local command-line tool. No vendor task quota or paid model API is required; optional sync needs separate setup and can incur server costs. Any.do and TickTick already have free plans, and TickTick includes recurrence free. This developer-oriented route does not provide equivalent graphical/mobile apps, push/location/WhatsApp reminders, calendar or habit views, collaboration, or a guaranteed import path.
Terminal-first, with a learning curve; Windows uses WSL. Not a polished mobile or graphical Things replacement. Optional multi-device sync requires a compatible service/server, administration and backups; version migration needs care. Notifications and team workflows are not equivalent to Todoist.
Each comparison covers the workflow described above, rather than every paid feature.