github.com/AliyunContainerService/cli@v0.0.0-20181009023821-814ced4b30d0/docs/reference/commandline/exec.md (about)

     1  ---
     2  title: "exec"
     3  description: "The exec command description and usage"
     4  keywords: "command, container, run, execute"
     5  ---
     6  
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    15  
    16  # exec
    17  
    18  ```markdown
    19  Usage:  docker exec [OPTIONS] CONTAINER COMMAND [ARG...]
    20  
    21  Run a command in a running container
    22  
    23  Options:
    24    -d, --detach         Detached mode: run command in the background
    25        --detach-keys    Override the key sequence for detaching a container
    26    -e, --env=[]         Set environment variables
    27        --help           Print usage
    28    -i, --interactive    Keep STDIN open even if not attached
    29        --privileged     Give extended privileges to the command
    30    -t, --tty            Allocate a pseudo-TTY
    31    -u, --user           Username or UID (format: <name|uid>[:<group|gid>])
    32    -w, --workdir        Working directory inside the container  
    33  ```
    34  
    35  ## Description
    36  
    37  The `docker exec` command runs a new command in a running container.
    38  
    39  The command started using `docker exec` only runs while the container's primary
    40  process (`PID 1`) is running, and it is not restarted if the container is
    41  restarted.
    42  
    43  COMMAND will run in the default directory of the container. If the
    44  underlying image has a custom directory specified with the WORKDIR directive
    45  in its Dockerfile, this will be used instead.
    46  
    47  COMMAND should be an executable, a chained or a quoted command
    48  will not work. Example: `docker exec -ti my_container "echo a && echo b"` will
    49  not work, but `docker exec -ti my_container sh -c "echo a && echo b"` will.
    50  
    51  ## Examples
    52  
    53  ### Run `docker exec` on a running container
    54  
    55  First, start a container.
    56  
    57  ```bash
    58  $ docker run --name ubuntu_bash --rm -i -t ubuntu bash
    59  ```
    60  
    61  This will create a container named `ubuntu_bash` and start a Bash session.
    62  
    63  Next, execute a command on the container.
    64  
    65  ```bash
    66  $ docker exec -d ubuntu_bash touch /tmp/execWorks
    67  ```
    68  
    69  This will create a new file `/tmp/execWorks` inside the running container
    70  `ubuntu_bash`, in the background.
    71  
    72  Next, execute an interactive `bash` shell on the container.
    73  
    74  ```bash
    75  $ docker exec -it ubuntu_bash bash
    76  ```
    77  
    78  This will create a new Bash session in the container `ubuntu_bash`.
    79  
    80  Next, set an environment variable in the current bash session.
    81  
    82  ```bash
    83  $ docker exec -it -e VAR=1 ubuntu_bash bash
    84  ```
    85  
    86  This will create a new Bash session in the container `ubuntu_bash` with environment 
    87  variable `$VAR` set to "1". Note that this environment variable will only be valid 
    88  on the current Bash session.
    89  
    90  By default `docker exec` command runs in the same working directory set when container was created.
    91  
    92  ```bash
    93  $ docker exec -it ubuntu_bash pwd
    94  /
    95  ```
    96  
    97  You can select working directory for the command to execute into
    98  
    99  ```bash
   100  $ docker exec -it -w /root ubuntu_bash pwd
   101  /root
   102  ```
   103  
   104  
   105  ### Try to run `docker exec` on a paused container
   106  
   107  If the container is paused, then the `docker exec` command will fail with an error:
   108  
   109  ```bash
   110  $ docker pause test
   111  
   112  test
   113  
   114  $ docker ps
   115  
   116  CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                   PORTS               NAMES
   117  1ae3b36715d2        ubuntu:latest       "bash"              17 seconds ago      Up 16 seconds (Paused)                       test
   118  
   119  $ docker exec test ls
   120  
   121  FATA[0000] Error response from daemon: Container test is paused, unpause the container before exec
   122  
   123  $ echo $?
   124  1
   125  ```