lxcattach

lxc-attach is a utility in the Linux Containers (LXC) toolset that allows a user to run a command inside a running container. By attaching to the container's namespaces, it provides direct access to the container's process space, filesystem view, and network environment, enabling interactive inspection and maintenance without starting a new container instance. The standard command is lxc-attach, occasionally written as lxcattach in manuals.

Typical usage is lxc-attach -n container-name -- /bin/bash to open an interactive shell inside the container. A non-interactive command can also be supplied after the -- separator, for example lxc-attach -n container-name -- ls /etc. If no command is given, an interactive session is started by default.

Under the hood, lxc-attach uses the container's namespaces to execute the specified command in the container's context. It can allocate a pseudo-terminal for interactive use and respects the container's user and mount namespace settings, so the command sees the container’s environment rather than the host's.

Access to lxc-attach is typically restricted to users with appropriate permissions, commonly root or a user with the necessary capabilities. Configuration and security policies may limit usage to protect the host system and other containers.

See also: lxc-console, lxc-start, lxc-stop.