github.com/docker/docker-ce@v17.12.1-ce-rc2+incompatible/components/cli/man/src/container/exec.md (about)

     1  Run a process in a running container.
     2  
     3  The command started using `docker exec` will only run while the container's primary
     4  process (`PID 1`) is running, and will not be restarted if the container is restarted.
     5  
     6  If the container is paused, then the `docker exec` command will wait until the
     7  container is unpaused, and then run
     8  
     9  # CAPABILITIES
    10  
    11  `privileged` gives the process extended
    12  [Linux capabilities](http://man7.org/linux/man-pages/man7/capabilities.7.html)
    13  when running in a container. 
    14  
    15  Without this flag, the process run by `docker exec` in a running container has
    16  the same capabilities as the container, which may be limited. Set
    17  `--privileged` to give all capabilities to the process.
    18  
    19  # USER
    20  `user` sets the username or UID used and optionally the groupname or GID for the specified command.
    21  
    22     The followings examples are all valid:
    23     --user [user | user:group | uid | uid:gid | user:gid | uid:group ]
    24  
    25     Without this argument the command will be run as root in the container.