csplit:tldr:a4bfa

The command csplit is used to split files based on specific criteria. Here is the explanation of the given command:

• csplit: It is the command to split files.
• -k: It is an option that tells csplit to retain all the split files even if they already exist.
• ${filename}: It is a placeholder for the name of the file that will be split.
• ${5}: This is an argument that specifies the pattern or line number at which the file should be split. In this case, ${5} represents the fifth pattern or line.
• ${*}: This signifies that csplit should split the file at every occurrence of the pattern specified by the previous ${5} argument.

Overall, this command splits the file ${filename} at every occurrence of the fifth pattern or line, retaining all split files even if they already exist.