lz4:tldr:64f97

The command "lz4 ${filename}" is using lz4, a lossless data compression algorithm, to compress or decompress the specified file.

Here's a breakdown of the components:

• "lz4": This is the command to invoke the lz4 compression utility.
• "${filename}": A placeholder that represents the actual filename or path of the file you want to compress or decompress. It should be replaced with the actual filename when executing the command.

By running this command, lz4 will either compress the specified file and create a compressed version, or it will decompress an already compressed file to its original format, depending on what the file actually is and the options used with the lz4 command.