Add format flag

[mrmara]

Usage:

lscompute --format plain|json

plain format is default

Exaple Output:

$ lscompute
cpus:
  - architecture: amd64
    manufacturer-id: AuthenticAMD
    flags: [fpu, vme, de, pse, tsc, msr, pae, mce, cx8,...]
memory:
  total-ram: 87.7G
  total-swap: 8.0G
disk:
  /var/lib/snapd/snaps:
    total: 1.8T
    avail: 41.1G
devices:
  - bus: pci
    slot: '0000:00:00.0'
    bus-number: "0x0"
    device-class: "0x600"
    vendor-id: "0x1022"
    device-id: "0x1122"
    subvendor-id: "0x17AA"
    subdevice-id: "0x512E"
    vendor-name: Advanced Micro Devices, Inc. [AMD]
    device-name: Krackan Root Complex
    subvendor-name: Lenovo
  - bus: pci
    slot: '0000:00:00.2'
    bus-number: "0x0"
    device-class: "0x806"
    vendor-id: "0x1022"
    device-id: "0x1123"
    subvendor-id: "0x17AA"
    subdevice-id: "0x512E"
    vendor-name: Advanced Micro Devices, Inc. [AMD]
    device-name: Krackan IOMMU
    subvendor-name: Lenovo
  - ...

{
  "cpus": [
    {
      "architecture": "amd64",
      "manufacturer-id": "AuthenticAMD",
      "flags": [
        "fpu",
        "vme",
        "de",
        "pse",
        "tsc",
        "msr",
        "pae",
        "mce",
        "cx8",
        ...
      ]
    }
  ],
  "memory": {
    "total-ram": 94220341248,
    "total-swap": 8589930496
  },
  "disk": {
    "/var/lib/snapd/snaps": {
      "total": 2011859927040,
      "avail": 44169400320
    }
  },
  "devices": [
    {
      "bus": "pci",
      "slot": "0000:00:00.0",
      "bus-number": "0x0",
      "device-class": "0x600",
      "vendor-id": "0x1022",
      "device-id": "0x1122",
      "subvendor-id": "0x17AA",
      "subdevice-id": "0x512E",
      "vendor-name": "Advanced Micro Devices, Inc. [AMD]",
      "device-name": "Krackan Root Complex",
      "subvendor-name": "Lenovo"
    },
    {
      "bus": "pci",
      "slot": "0000:00:00.2",
      "bus-number": "0x0",
      "device-class": "0x806",
      "vendor-id": "0x1022",
      "device-id": "0x1123",
      "subvendor-id": "0x17AA",
      "subdevice-id": "0x512E",
      "vendor-name": "Advanced Micro Devices, Inc. [AMD]",
      "device-name": "Krackan IOMMU",
      "subvendor-name": "Lenovo"
    },
    {
      ...
    }
  ]
}

[Copilot]

Pull request overview

This PR adds a --format CLI flag to lscompute to support multiple output serializations, making the default output a human-readable “plain” summary while preserving JSON output for machine consumption.

Changes:

• Add --format flag to select plain (default) or json output.
• Introduce pkg/machine formatting layer (Marshal) with a plain-text renderer.
• Update usage documentation and add example-based tests for both formats.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 6 comments.

File	Description
README.md	Updates usage docs to describe default plain output and --format flag.
cmd/lscompute/main.go	Adds flag parsing and routes output through machine.Marshal.
pkg/machine/format.go	Implements format selection + plain-text rendering and byte formatting helpers.
pkg/machine/format_test.go	Adds Go examples for JSON and plain output rendering using test data.

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