> ## Documentation Index
> Fetch the complete documentation index at: https://docs.bluejutzu.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# inspect

> Report what a file actually is.

```bash theme={"system"}
bmux inspect <file> [--json]
```

`inspect` reads a file's **contents** to work out what it is, rather than trusting the extension.
It writes nothing and changes nothing.

```bash theme={"system"}
bmux inspect photo.jpg
```

```
photo.jpg
  size: 11519 bytes
  detected type: image/jpeg
  dimensions: 1600x1200
  format: jpeg
  alpha channel: false
  color space: srgb
  EXIF present: false
```

## Arguments

<ParamField path="file" type="string" required>
  The file to inspect. Only one at a time.
</ParamField>

## Options

<ParamField query="--json" type="boolean" default="false">
  Emit machine-readable JSON instead of the human summary.
</ParamField>

## JSON output

```bash theme={"system"}
bmux inspect photo.jpg --json
```

```json theme={"system"}
{
  "path": "photo.jpg",
  "sizeBytes": 11519,
  "detectedMimeType": "image/jpeg",
  "detectedExtension": "jpg",
  "image": {
    "format": "jpeg",
    "width": 1600,
    "height": 1200,
    "hasAlpha": false,
    "colorSpace": "srgb",
    "hasExif": false
  }
}
```

<ResponseField name="path" type="string" required>
  The path you passed in, unchanged.
</ResponseField>

<ResponseField name="sizeBytes" type="number" required>
  Size on disk, in bytes.
</ResponseField>

<ResponseField name="detectedMimeType" type="string">
  Read from the file's magic bytes. Absent if nothing recognisable was found.
</ResponseField>

<ResponseField name="detectedExtension" type="string">
  The canonical extension for that type, which may differ from the filename.
</ResponseField>

<ResponseField name="image" type="object">
  Present only if the file could be decoded as an image.

  <Expandable title="image">
    <ResponseField name="format" type="string">
      The decoder's name for the format, e.g. `jpeg`.
    </ResponseField>

    <ResponseField name="width" type="number">
      Width in pixels.
    </ResponseField>

    <ResponseField name="height" type="number">
      Height in pixels.
    </ResponseField>

    <ResponseField name="hasAlpha" type="boolean">
      Whether the image carries an alpha channel.
    </ResponseField>

    <ResponseField name="colorSpace" type="string">
      Colour space, e.g. `srgb`.
    </ResponseField>

    <ResponseField name="hasExif" type="boolean">
      Whether EXIF is present — not what it contains.
    </ResponseField>
  </Expandable>
</ResponseField>

## Spotting a mislabelled file

Because detection ignores the extension, a renamed file gives itself away — the detected type won't
match the name:

```bash theme={"system"}
bmux inspect screenshot.jpg --json
```

```json theme={"system"}
{
  "path": "screenshot.jpg",
  "detectedMimeType": "image/png",
  "detectedExtension": "png"
}
```

That file is a PNG regardless of what it's called, and bmux will treat it as one.

## Using it in a script

`--json` pairs with [jq](https://jqlang.github.io/jq/) for quick checks:

```bash theme={"system"}
# every image wider than 2000px
for f in photos/*; do
  w=$(bmux inspect "$f" --json | jq '.image.width // 0')
  [ "$w" -gt 2000 ] && echo "$f is ${w}px wide"
done
```

<Note>
  `inspect` exits non-zero if the file can't be read at all. A file that reads fine but isn't a
  decodable image still exits `0` — `image` is simply omitted, which is a result rather than an
  error.
</Note>