pngcrush:tldr:f016b

The command "pngcrush ${in-png} ${out-png}" is used to compress and optimize PNG image files using the "pngcrush" tool.

Here is a breakdown of the command:

• "pngcrush" is the name of the tool or program being executed.
• "${in-png}" represents the input PNG file. The "${in-png}" syntax indicates that the value for this variable should be provided when running the command. It is typically the path or name of the PNG file you wish to compress.
• "${out-png}" represents the output PNG file. Similar to "${in-png}", it is a variable that should be replaced with the desired path or name of the compressed PNG file generated by the command.

When you execute this command, the "pngcrush" tool takes the input PNG file, performs compression and optimization techniques, and saves the resulting compressed file with the specified name or path denoted by "${out-png}". The compressed PNG file should have a smaller file size while preserving the visual quality of the image.