DOS Cheat Sheet for Computer Tools for Engineers

Here is a short "cheat sheet" of DOS basics. You will need to know this information to manage files on your floppy and hard-disk.

Basic concepts (files and directories):

A file contains data or a program and is stored in a directory. A filename can have a maximum of 8 letters followed by a "." and three more letters. For example, salary.mcd is a MathCAD file, grades.xls is an Excel file, prog1.f is a FORTRAN file, and prog1.exe is an executable file (i.e., an application).

A directory is analogous to a file folder. Files are stored in directories, The "root directory" on a PC hard-disk is c:\. On a floppy disk the root directory is a:\ or b:\.

Commands to manipulate files:

copy x y - Copies file x to file y. Files x and y can be specified with their disk and directory name. For example, copy user.dat a:\kjc copies file user.dat in the current directory to directory \kjc on the floppy disk.
erase x.dat - Erases file x.dat in the current directory.
rename x.dat x.old - Renames a file with name x.dat to a file with name x.old in the current directory.
dir - Lists all files in the current directory.
prompt $p$g - Command to make the "DOS prompt" indicate the current directory (e.g., as in c:\temp\>).

Commands to manipulate directories:

md c:\x - Makes directory x as a "first level" directory from the hard-disk root.
cd c:\x - Changes to directory x from the root. Note that cd c:\ will always get you back to the hard-disk root directory.
rd c:\x - Removes directory x from the hard-disk root. The directory must first be empty (i.e., all files erased).

Formatting a diskette:

Formatting a diskette "cleans" the diskette (erasing any files) and prepares it for use. All brand new diskettes must be formatted. The format command is:

format a: - Formats the diskette in the a: drive.
format a: /Q - Does a quick format.

When formatting is complete, you will be asked for a "volume name", just press Enter.

Some simple examples (that also show some new things):

Here is an example of copying all files from a floppy disk (a:\) to an existing directory named c:\kjc on the hard-disk...
And now copying all of the MathCAD files only back to the floppy disk...
Here we format a floppy disk and create three directories...
Here we create a directory, change to it, copy a file from the floppy disk to this now "current" directory, erase the file, change back to the root directory, and finally remove the created directory.
Here we copy all files from a floppy disk (that has no directories other than the root directory) to c:\. Then we copy the files back to another diskette. This is an example of how you can back-up the files on your diskette.

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Last updated by Ken Christensen on AUGUST 12, 1999