cron/crontab/at

      Is the time-based job scheduler in Unix-like computer operating systems. 
      Enables users to schedule jobs (commands or shell scripts) to run periodically
       at certain times or dates. 
      It is commonly used to automate system maintenance or administration.
      
      __Crontab_ (cron table) file, a configuration file that specifies shell 
      commands to run periodically on a given schedule. 
      

• Wikipedia
• Sean Edwards
• Harley Hahn's Guide to Unix and Linux

Let's talk.

talk is a program that provides visual communication between two parties via text through the terminal. ( talk person ) Using this command alone will prompt the second party with the following message:

• Message from TalkDaemon@his_machine…
• talk: connection requested by your_name@your_machine.
• talk: respond with: talk your_name@your_machine

At this point, the terminal will be now a chat window between the two parties. Both parties can type at the same time since their text appears in different parts of the window. To exit the window, use CTRL + C

ytalk is a program that provides visual communication between multiple parties via text through the terminal. It's basically the same program as talk, only it allows for multiple connections. ( ytalk [-s] [-Y] [-E] [-i] [-q] [-v] [-h hostname_or_ip] username… )

The username portion can be formatted in the following ways:

• name - some user on your machine
• name@host - some user on a different machine
• name#tty - some user on a particular terminal
• name#tty@host - some user on a particular tty on a different machine
• name@host#tty - same as “name#tty@host”
• aliasname - an alias defined in your .ytalkrc

You can also specify multiple usernames on the command line with ytalk ( ytalk george fred@hissun.edu marc@grumpy.cc )

Say hello to the options:

• -s option starts your YTalk window in a shell.
• -Y option requires a capital Y or N as an answer to any yes/no question.
• -E option requires you to press escape once before answering a yes/no question (for people who type looking at the keyboard).
• -i option disables the auto-invite port (meaning you won't see “talk to blah@blah.com”, but your talk daemon will beep you instead).
• -q option causes YTalk to prompt you before quitting.
• -v option prints the program version and exits.
• -h option specifies the name or address of the local machine; this is useful on multi-homed machines, or virtual hosts, to specify which network interface to use for communication.

More to be added with more awesome details to come.

• http://linux.about.com/od/commands/l/blcmdl1_talk.htm
• http://linux.die.net/man/1/ytalk

Demonstration of the indicated keyword.

lab46:~$ cd src
lab46:~/src$ gcc -o hello hello.c
lab46:~/src$ ./hello
Hello, World!
lab46:~/src$