inspect

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.

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

string

required

The file to inspect. Only one at a time.

Options

boolean

default:"false"

Emit machine-readable JSON instead of the human summary.

JSON output

bmux inspect photo.jpg --json

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

string

required

The path you passed in, unchanged.

number

required

Size on disk, in bytes.

string

Read from the file’s magic bytes. Absent if nothing recognisable was found.

string

The canonical extension for that type, which may differ from the filename.

object

Present only if the file could be decoded as an image.

Show image

string

The decoder’s name for the format, e.g. jpeg.

number

Width in pixels.

number

Height in pixels.

boolean

Whether the image carries an alpha channel.

string

Colour space, e.g. srgb.

boolean

Whether EXIF is present — not what it contains.

Spotting a mislabelled file

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

bmux inspect screenshot.jpg --json

{
  "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 for quick checks:

# 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

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.

Getting started

Commands

Arguments

Options

JSON output

Spotting a mislabelled file

Using it in a script

​Arguments

​Options

​JSON output

​Spotting a mislabelled file

​Using it in a script

Arguments

Options

JSON output

Spotting a mislabelled file

Using it in a script