The crontab file format consists of six fields: minute, hour, day of month, month, day of week, and command.
The user-specific crontab files have the same format as the global /etc/crontab file, except that they do not have the username field. The username field is only present in the system-wide crontab files and specifies which user will run the cron job. The year field is not a valid crontab field and is not supported by cron. References:
* Scheduling Cron Jobs with Crontab | Linuxize
* Crontab Explained in Linux [With Examples]

14
Explanation:
To find the number of IP-addresses that can be used for unique hosts inside an IPv4 subnet, we need to calculate the number of bits that are used for the host part of the IP address. The host part is the part that is not used for the network prefix, which is indicated by the slash notation (/) followed by a number. The number after the slash represents the number of bits that are used for the network prefix, out of the total 32 bits of an IPv4 address. The remaining bits are used for the host part. For example, in the subnet 192.168.2.128/28, the number 28 means that the first 28 bits are used for the network prefix, and the last 4 bits are used for the host part.
The number of IP-addresses that can be used for unique hosts is equal to 2^n - 2, where n is the number of bits in the host part. The -2 is because the first and the last IP addresses in a subnet are reserved for the network address and the broadcast address, respectively, and cannot be assigned to hosts. Therefore, in the subnet 192.168.2.128/28, the number of IP-addresses that can be used for unique hosts is 2^4 - 2, which is 14.
Reference:
IPv4 - Subnetting - Online Tutorials Library
IP Subnet Calculator

The lpr command is a legacy program provided by CUPS for sending files to the printer queues on the command line. It is one of the Berkeley (lpr) printing commands that CUPS supports for compatibility with other Unix-like systems. The lpr command accepts one or more filenames asarguments and sends them to the default or specified printer. It also supports several options to control the printing process, such as the number of copies, the page size, the orientation, and the priority. The lpr command is equivalent to the lp command, which is one of the System V (lp) printing commands that CUPS also supports. However, the lp command has more options and features than the lpr command, and is recommended for use with CUPS. References:
* Command-Line Printing and Options - CUPS
* Command-Line Printer Administration - CUPS
* Linux cups tutorial for beginners - Linux Tutorials - Learn Linux ...
* CUPS Command-Line Utilities - Configuring and Managing ... - Oracle