shell

A shell acts as the interface between a user and an operating system in which the user can launch other programs or access directories. There are two types of shells, command line or graphical. A windows operating system uses the graphical interface Windows Explorer to allow users to access programs and view files, where as a Unix systems tend to use the command line interfaces wherein text is typed at the command line prompt in order to launch programs and enter commands to view directories.

• http://en.wikipedia.org/wiki/Shell_(computing)
• Harley Hahn's Guide to Unix and Linux by Harley Hahn

here string

The symbol for a here string is «< . A here string puts whatever input you want into a command. Like bc «< 2+2 sends 2+2 into the calculator and it will come back as 4. So it does the operation in one step instead of going into the calculator and typing 2+2 or whatever you want to solve.

* Notes from when we talked about here strings and the binary calculator.

Demonstration of here string

lab46:~$ bc <<< 86+24 
110