tor

Connect to the Tor network

$ tor

$ tor --config

$ tor --status

$ tor --client

$ tor --relay

$ tor --bridge

$ tor --hidden-service

tor [options]

-h, --help
    Display command synopsis and exit

--version
    Print Tor version and exit

-f FILE, --torrc-file FILE
    Use FILE as configuration instead of torrc

--defaults-torrc FILE
    Use FILE as defaults-torrc

--torrc-files torrc1 torrc2 ...
    Read multiple torrc files successively

-m SIZE, --MaxMemInQueues SIZE
    Limit memory queues to SIZE MB

--quiet
    Don't output normal startup messages

--runasdaemon [0|1]
    Fork and daemonize after startup (Unix)

--pidfile FILE
    Save PID to FILE

--verify-config
    Validate configuration and exit

--list-fingerprint
    Print relay fingerprint

--list-torrc-options
    List all torrc options

--ignore-missing-torrc
    Start despite missing torrc

--DataDirectory DIR
    Store working data in DIR

--SocksPort [ADDRESS:]PORT
    Set SOCKS proxy port (default 9050)

--ControlPort PORT
    Enable control port on PORT (default 9051)

--Log level file|syslog
    Set logging level and destination

Tor (The Onion Router) is free software and open network that helps defy censorship, avoid surveillance, and protect privacy by routing traffic through thousands of volunteer-operated relays worldwide. Each relay peels off a layer of encryption, like layers of an onion, concealing the origin and destination of data.

The tor command launches the Tor process, configurable as a client (for anonymous browsing via SOCKS proxy on port 9050), relay, bridge (for censored regions), or exit node. Most settings come from torrc files (/etc/tor/torrc or ~/.tor/torrc), but command-line options override them. Tor supports circuit building, hidden services (.onion sites), pluggable transports, and a control port for runtime management.

Apps like Firefox with Tor Browser bundle it for easy use. Running relays strengthens the network but exit nodes risk seeing plaintext traffic, with legal implications. Bridges evade detection. Tor resists traffic analysis but isn't foolproof against advanced adversaries. Regularly update for security fixes.

Tor anonymizes TCP traffic only; UDP/DNS leaks possible without proper setup. Exit nodes see unencrypted data. High CPU/memory use on relays. Blocked in some countries; use bridges. Not for high-bandwidth or real-time apps.

Main: /usr/local/etc/tor/torrc or /etc/tor/torrc. Command-line options override torrc directives. Use --dump-config to inspect effective config.

Enable --ControlPort 9051 for tools like nyx or stem to query circuits, reload config, signal NEWNYM.

Configure HiddenServiceDir and HiddenServicePort in torrc for .onion sites.

Developed 2002 by Roger Dingledine, Nick Mathewson, Paul Syverson (US Naval Research Lab). First release 2004. Tor Project nonprofit founded 2006 for maintenance. Command evolves with versions; v0.4.8 (2024) adds security, performance.

torsocks(1), torify(1), nyx(1), stem(1)