Concepts Glossary 156 Getting Started Guide Scripts in Linux can be compared to batch files in DOS, although several differ- ent scripting languages are available in Linux, all of which are more comprehen- sive in their features than DOS batch commands. SCSI SCSI is an interface method used to connect storage and other devices to your computer. Common examples of SCSI devices include hard disks, tape drives, CD-ROMs, and even scanners and plotters. SCSI provides a much faster interface than IDE, but it can be harder to configure and it generally costs more to buy SCSI devices. Linux includes strong support for SCSI devices, although you often must load a kernel module to support the SCSI device that you want to access. Multiple SCSI devices can be attached to a single SCSI controller card in your computer. Each SCSI device provides it’s own ID number to the controller card, which you can use to access it. The first SCSI hard disk in Linux is referred to as /dev/sda; the second as /dev/ sdb, and so forth. Shell A Linux shell is a command interpreter that provides a command line interface to launch programs, run scripts, manage multiple processes, and so forth. The default shell in Linux is called bash. Other shells that are available for Linux include tch, csh, and the korn shell. See also command line Shutdown A Linux system must be gracefully shut down before turning off the system power, otherwise you risk loosing data or corrupting files that are being held in memory as Linux works with them. The shutdown command, the reboot command, or the Ctrl+Alt+Delete key sequence all begin a process to close all Linux programs, save data to disks, and gracefully exit. In addition to these commands, you can choose System shutdown from the graphical login.