Docker - Inspect image: understand the default command of an image

• Inspect an image can understand what command will be executed by default

docker image inspect ubuntu

[

    {

        "Id": "sha256:a2a15febcdf362f6115e801d37b5e60d6faaeedcb9896155e5fe9d754025be12",

        "RepoTags": [

            "ubuntu:latest"

        ],

        "RepoDigests": [

            "ubuntu@sha256:d1d454df0f579c6be4d8161d227462d69e163a8ff9d20a847533989cf0c94d90"

        ],

        "Parent": "",

        "Comment": "",

        "Created": "2019-08-15T07:28:14.830150536Z",

        "Container": "41b694b9b42f9c5ef7fb40c24272927a727a6d6cb8120bb3eae5849ceb9bee77",

        "ContainerConfig": {

            "Hostname": "41b694b9b42f",

            "Domainname": "",

            "User": "",

            "AttachStdin": false,

            "AttachStdout": false,

            "AttachStderr": false,

            "Tty": false,

            "OpenStdin": false,

            "StdinOnce": false,

            "Env": [

                "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"

            ],

            "Cmd": [

                "/bin/sh",

                "-c",

                "#(nop) ",

                "CMD [\"/bin/bash\"]"

            ],

            "ArgsEscaped": true,

            "Image": "sha256:bcbe079849fdbb50b3eb04798547e046bdbc82020b8b780d767cf29f7e60b396",

            "Volumes": null,

            "WorkingDir": "",

            "Entrypoint": null,

            "OnBuild": null,

            "Labels": {}

        },

        "DockerVersion": "18.06.1-ce",

        "Author": "",

        "Config": {

            "Hostname": "",

            "Domainname": "",

            "User": "",

            "AttachStdin": false,

            "AttachStdout": false,

            "AttachStderr": false,

            "Tty": false,

            "OpenStdin": false,

            "StdinOnce": false,

            "Env": [

                "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"

            ],

            "Cmd": [

                "/bin/bash"

            ],

            "ArgsEscaped": true,

            "Image": "sha256:bcbe079849fdbb50b3eb04798547e046bdbc82020b8b780d767cf29f7e60b396",

            "Volumes": null,

            "WorkingDir": "",

            "Entrypoint": null,

            "OnBuild": null,

            "Labels": null

        },

        "Architecture": "amd64",

        "Os": "linux",

        "Size": 64185488,

        "VirtualSize": 64185488,

        "GraphDriver": {

            "Data": {

                "LowerDir": "/var/lib/docker/overlay2/b6f45f91ad1f6356deb2c2ab3d04305cfcf0a5eedd3fed58e7059f901fbf6c4d/diff:/var/lib/docker/overlay2/dd6b618cd5cb79f5e029942234a1aeadead024082bade5bd2321e77eb504d6f1/diff:/var/lib/docker/overlay2/0fec4af91d36748a2b39c11fcd7f73bc015144ea28c7ff4234948d97e5d839b2/diff",

                "MergedDir": "/var/lib/docker/overlay2/462cef4adf522157e3ca7b7a86af6341f141c21da54e30234c2a35264a01dae4/merged",

                "UpperDir": "/var/lib/docker/overlay2/462cef4adf522157e3ca7b7a86af6341f141c21da54e30234c2a35264a01dae4/diff",

                "WorkDir": "/var/lib/docker/overlay2/462cef4adf522157e3ca7b7a86af6341f141c21da54e30234c2a35264a01dae4/work"

            },

            "Name": "overlay2"

        },

        "RootFS": {

            "Type": "layers",

            "Layers": [

                "sha256:6cebf3abed5fac58d2e792ce8461454e92c245d5312c42118f02e231a73b317f",

                "sha256:f7eae43028b334123c3a1d778f7bdf9783bbe651c8b15371df0120fd13ec35c5",

                "sha256:7beb13bce073c21c9ee608acb13c7e851845245dc76ce81b418fdf580c45076b",

                "sha256:122be11ab4a29e554786b4a1ec4764dd55656b59d6228a0a3de78eaf5c1f226c"

            ]

        },

        "Metadata": {

            "LastTagTime": "0001-01-01T00:00:00Z"

        }

    }

]

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