parallel:tldr:44656

The command you provided is using the parallel command to run multiple instances of gzip in parallel on the given input files.

Here is a breakdown of the command:

• parallel is a command-line utility that allows running multiple instances of a command in parallel.
• gzip is a compression utility used to compress files.
• ::: is used as a separator to indicate the list of files that will be processed in parallel.
• ${file1} ${file2} ${file3} are placeholders for the file names or paths that will be compressed. These should be replaced with the actual file names or paths you want to gzip.

Overall, the command will compress the files specified by file1, file2, and file3 using gzip in parallel, potentially increasing the compression speed when dealing with multiple files.