Purpose

countdown command in all languages possible. It is an adventure in chrestomathy. We seek to explore following.

• How it is to write something useful in a particular language and not just 'Hello World'.

• To have an opportunity to understand things that are woven around a particular language and make up important part of the overall developer expirience. This includes communities, libraries, package management, environment setup etc. Ideally entire expirience should be documented as well.

Specification

• countdown should refer to a specific binary and should not be a binary command. E.g. countdown may be aliased to countdown-node to showcase the command implemented using Node runtime. Of course countdown-node can be used directly as well.

• Following all simply outputs Time is now! string.

  • countdown outputs immediately as there is no duration provided. Here the duration is taken to be 0.

  • countdown --milliseconds 2000 or countdown -k 2000 outputs after 2000 milliseconds.

  • countdown --seconds 20 or countdown -s 20 outputs after 20 seconds.

  • countdown --minutes 10 or countdown -m 10 outputs after 10 minutes.

  • countdown --minutes 10.5 or countdown -m 10.5 outputs after 10.5 minutes.

  • countdown --hours 2 or countdown -h 2 outputs after 2 hours.

  • countdown --hours 1.5 or countdown -h 1.5 outputs after 1.5 hours.

  • countdown -m 2.5 -s 15 outputs after 150+15 seconds. Various such combination should be possible.

  • Options aliases list (and tolerance to spelling mistakes)

    • k, mil, mils, mill, mills, milisecond, millisecond, miliseconds, milliseconds
    • s, sec, secs, second, seconds
    • m, min, mins, minute, minutes
    • h, hr, hrs, hour, hours

  • countdown --help displays the usage and exits.

  • countdown --version displays the version and which implementation it is pointing to and exits.

• .countdownrc file should be consulted.

• Support for installation.

• Support for uninstallation.

Aliasing

• Use alias to alias countdown to a specific implementation. E.g., following code aliases to a Node implementation.

   alias countdown='countdown-node'
  

• Use unalias to remove the alias.

   unalias countdown
  

• If you want to see which implementation the countdown is aliased to, use following command.

   alias | grep 'countdown'