How to use the command "identify" (with examples)
The “identify” command is a part of the ImageMagick software suite and is used to describe the format and characteristics of one or more image files. It is a versatile tool that provides valuable information about images, such as format, dimensions, color space, and more.
Use case 1: Describe the format and basic characteristics of an image
Code:
identify path/to/image
Motivation: This use case is ideal when you need quick information about an image file, such as its format and basic characteristics. By simply providing the path to the image file, you can obtain a summary of important details.
Explanation: “identify” is followed by the path to the image file. This command will output the format (e.g., JPEG, PNG) and basic characteristics, including the image dimensions and color space. It provides a concise overview of the image file.
Example output:
path/to/image.jpg JPEG 1024x768 sRGB 8-bit
Use case 2: Describe the format and verbose characteristics of an image
Code:
identify -verbose path/to/image
Motivation: In some cases, you may require more detailed information about an image, such as its compression type, color profiles, or pixel values. The use of the “-verbose” flag provides a comprehensive output.
Explanation: The “-verbose” flag is added to the “identify” command followed by the path to the image file. This command provides an extended description of the image, including attributes like resolution, colorspace, compression type, and color profiles.
Example output:
Format: JPEG (Joint Photographic Experts Group JFIF format)
Geometry: 1024x768
Resolution: 96x96 pixels per inch
Class: DirectClass
Type: TrueColor
Colorspace: sRGB
Compression: JPEG
Quality: 92
Orientation: TopLeft
Depth: 8-bit
Use case 3: Collect dimensions of all JPEG files in the current directory and save them into a CSV file
Code:
identify -format "%f,%w,%h\n" *.jpg > path/to/filelist.csv
Motivation: When you have a large number of images and you need to retrieve their dimensions for further analysis or documentation, using this command can streamline the process by generating a CSV file.
Explanation: “identify” is used with the “-format” option followed by a format string “%f,%w,%h\n” to specify the output format as filename, width, height, and a new line. The “*.jpg” wildcard is used to collect all JPEG files in the current directory. The resulting dimensions are then redirected to a CSV file using the “>” operator.
Example output (filelist.csv):
image1.jpg,800,600
image2.jpg,1024,768
image3.jpg,1280,720
Conclusion:
The “identify” command is a powerful tool for obtaining essential information about image files. Whether you need a quick overview or detailed characteristics, it provides valuable insights into image format, dimensions, color space, and more. Additionally, it can be used to collect image dimensions in bulk and save them into a CSV file, making it a practical choice for various use cases in image analysis and management.
