CLI System Disks

`ed system disks`

Lists the mounted volumes with their size, free space and how full they are.

ed system disks [--json]

Options

Name	Type / values	Default	What it does
`--json`	flag	off	Emit JSON on stdout instead of the table.
`--help`, `-h`	flag	off	Print the help for this command on stdout and exit 0.

The table has one row per volume, and prints its headings even when there are no rows:

$ ed system disks
VOLUME        MOUNT  SIZE    FREE    USED
Macintosh HD  /      494 GB  170 GB  66%

`--json` shape

Six keys, always all six:

{
  "battery": {
    "percent": 99,
    "status": "Finishing Charge"
  },
  "fans": [],
  "filesystems": [
    {
      "availableKB": 166164022,
      "filesystem": "Macintosh HD",
      "mount": "/",
      "totalKB": 482797652,
      "usedKB": 316633630,
      "usedPercent": 65.58309235522131
    }
  ],
  "gpu": null,
  "platformProfile": null,
  "temperatures": []
}

filesystem is the volume's name, not its device node, and mount is where it is mounted. usedKB is totalKB minus availableKB, and usedPercent is usedKB over totalKB.

battery is read from pmset -g batt and carries percent and a capitalised status such as Charging, Discharging or Finishing Charge. It is null on a Mac with no battery, and null rather than missing, so the key is always there.

temperatures, fans, platformProfile and gpu are part of the shared report shape the Linux collector fills in for a remote machine. The local sampler collects none of them, so on this Mac the arrays are always empty and the objects are always null. No ed command prints a remote machine's slow record either: ed machines metrics keeps the sample half and drops the volume, battery, temperature, fan, platform profile and GPU record, which reaches the app's Machines window instead. The fields, when a machine does report them, are:

{
  "fans": [
    {
      "label": "cpu_fan",
      "rpm": 3200
    }
  ],
  "gpu": {
    "memTotalMB": 8188,
    "memUsedMB": 1204,
    "name": "NVIDIA GeForce RTX 4060",
    "temperature": 47,
    "utilPercent": 12
  },
  "platformProfile": {
    "choices": [
      "low-power",
      "balanced",
      "performance"
    ],
    "current": "balanced"
  },
  "temperatures": [
    {
      "celsius": 43.5,
      "label": "Package id 0"
    }
  ]
}

The fan label comes from the hwmon sensor label when present and otherwise from the hwmon device plus fan index. rpm is a whole number. Platform profile names come directly from the two ACPI sysfs files and stay in the order the machine reports them.

Examples

ed system disks
ed system disks --json
ed system disks --json | jq -r '.filesystems[] | "\(.mount) \(.usedPercent | floor)%"'

Behaviour notes

Read only, instant, and needs neither the app nor a permission. The one subprocess it runs is pmset, for the battery line, and a pmset that fails to run is reported as battery: null rather than as an error.

Only volumes macOS marks browsable and not hidden, and that report a capacity above zero, are listed, so the Preboot, Recovery and VM volumes that mount and df show do not appear here.

Free space is the space macOS calls available for important usage, which counts purgeable caches it would evict for you. That is the figure Finder shows, and it is usually larger than what df prints for the same volume.

This is one of the few commands that does not run inside the CLI's failure wrapper, which changes nothing you can observe: the top level reports and codes a failure identically.