head:tldr:b6b93

The head command is used to display the beginning lines of a file. In the given command:

head --bytes -${count} ${filename}

• --bytes is an option for head that specifies to display the specified number of bytes instead of lines.
• - before ${count} is used to indicate that count is a negative number, meaning to display bytes from the end of the file rather than the beginning.
• ${count} is the argument that determines the number of bytes to be displayed. It should be replaced with a specific number.
• ${filename} is the argument that specifies the file whose contents will be displayed. It should be replaced with the name (including the path, if necessary) of the actual file.

Overall, this command will display the last count number of bytes from the file named ${filename}.