DOS characters and commands

w^rl0rdw^rl0rd Member Posts: 329
Does anyone know an easy way to remember what characters are legal/illeagal in DOS? Also, does anyone know how to remember which DOS commands are internal or external?


  • RussSRussS Member Posts: 2,068
    Hmm - nothing comes to mind. I've been using DOS commands for years and I still occasionally use the wrong one.
    The only commands I clutter my crain with are DIR and help /? ... lol
    FIM website of the year 2007
  • WebmasterWebmaster Admin Posts: 10,292 Admin
    The way to remember them is 'simply' to use them... that's what you should be able to do when A+ certified, thats what your tested on. Just play around with the various commands. No need to try every option and parameter, just the obvious ones.

    Internal command reside within, external commands exists as a file on your hard drive. From the exam objectives, take the listed commands, and do a search on your hard disk for the file. (e.g. in \windows\command\ or \system32\ folder) to find out which are internal/external if your book doesn't list them. Common examples of internal commands are: cd, md, del and common examples of external commands are mem, fdisk, format
  • WebmasterWebmaster Admin Posts: 10,292 Admin
    I just wanted to add, that although most of these commands originated in DOS, for the CompTIA exam and MS Windows these are command-line utilities icon_wink.gif
    DOS is not longer part of the exam and most commands have changed a bit and have additional Windows specific options.
  • headcaseheadcase Member Posts: 30 ■■□□□□□□□□
    Internal - DOS commands that are built into the Operating System

    External - Commands that must be executed from a file

    One way to remember them, if you consider this a way, is that Internal commands are basic, while external commands are stored on disk

    internal commands are located in the COMMAND.COM program, and are loaded into memory during the bootup process. For example, the DIR command is built into the OS and is a basic command.

    external commands are stored on a disk. For example, to run FDISK (more advanced command) you would need a bootable floppy which contained the FDISK file.

    Hope this helps
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