Getting Started Guide 145 There is a package Linux package of DOS tools called mtools that let you work with DOS files within Linux. Utilities such as mcopy (for copying ), mdir (for listing ) and mdel (for deleting) can all be used to work with DOS files. These tools are useful for exchanging files with Windows/DOS systems and Linux using DOS floppy diskettes. (However, you can also use /auto/floppy to copy files to a DOS floppy diskette, using standard Linux commands.) Environment variables Environment variables provide information for programs running on your Linux system. For example, an environment variable named HOME contains the path to reach your home directory. Any program that needs to determine where your home directory is located can ask for the value of the HOME environment vari- able. Linux includes a few standard environment variables such as the network host- name of your computer and the location of your home directory. In addition, many programs set up environment variables as part of their installation so that they can locate components of your system as they run. If you need to set an environment variable, you would normally add an export line to a shell start-up file (such as .bashrc in your home directory). If you used the bash shell (which is assigned by default), the line you add would look some- thing like this (variable names are normally in upper case letters): export VARIABLE_NAME=variable_value Environment variables are part of each user’s account infor- mation. If you log in using a different user account, many of your environment variables could change. If you used the csh shell, to set an environment variable you would add a setenv line to the .cshrc file in your home directory that looked something like this: CD cd DIR ls -l (the -l option provides a detailed listing similar to DIR) TYPE filename | MORE less filename DEL filename rm filename DOS Command Linux equivalent TABLE 6 Common DOS commands and their Linux equivalents