  -8-




  CHAPTER 1 / GENERAL CONCEPTS


  You can start using Take Command as soon as you finish installing
  it, because it is compatible with the traditional commands you're
  probably used to.  But most users find that the more they know
  about their computer systems, the more power they get from our
  products.  And, the more experience they gain, the more they want
  to know about their computer system as a whole.

  This section of the manual explains some fundamental concepts
  about your computer, operating system, and Take Command.  It
  should help you understand the terms and concepts in the pages
  that follow.  If you find some of the concepts overwhelming, just
  remember that they are here when you need them.  If you find this
  material too simple, skim over the topics and then go on to the
  next section.  Each topic in this chapter is independent, so if
  you read it straight through you won't necessarily find a natural
  "flow" from one topic to another.


  Operating Systems and Command Processors

       This section explains briefly what an operating system is,
       what a command processor is, and how Take Command works under
       Windows and OS/2.

       An operating system is nothing more than a collection of
       software.  However, unlike application software, which
       performs a specific, user-oriented task (such as creating and
       printing documents, or performing calculations on rows and
       columns of numbers), operating system software is designed to
       perform some special functions.  The operating system
       typically:

            *  Starts the computer system.  The operating system is
               the first software loaded when you turn on the
               computer.

            *  Provides services to other software.  These include
               basic file access, assignment of your computer's
               memory for use by different programs, and the control
               of hardware devices like the keyboard, display,
               printer, and serial ports.

            *  Ensures that programs don't interfere with each other
               while they are running.

            *  Provides a way for you to start programs to do your
               work.

            *  Includes utilities to control and manage your system,
               for example to organize disks and files, display
  -9-



               status information, or adjust your system for
               international conventions.

       More complex operating systems may include many more
       functions, such as built-in network connections, the ability
       to switch rapidly between many tasks, support for high-
       quality sound output, and so on.

       Take Command works with several different operating systems:

            When you load Windows 3.x or Windows for Workgroups,
            Windows combines with DOS to provide operating system
            functions for Windows applications.  You can also run
            Windows within the OS/2 operating system.  Take
            Command/16 will work with any of these versions of
            Windows.

            Windows 95 starts from DOS, and then takes over
            essentially all operating system functions itself.  Take
            Command/32 works with the Windows 95 operating system.

            Windows NT and OS/2 are, by themselves, complete
            operating systems.  They do not require DOS or any other
            foundation to run.  Take Command/32 works with Windows
            NT version 3.5 and later, and Take Command for OS/2
            works with OS/2 version 2.1 and later.

       In all of these operating systems, Take Command operates as a
       command processor:  a program that accepts your instructions
       and carries them out.  The basic operation of a command
       processor is very simple.  It prompts you for a command, you
       type in the command, the command processor executes it, and
       the cycle repeats.  This is sometimes called a "command line"
       interface, because commands are typically executed line by
       line.

TC16   You can also use Take Command/16 as your Windows shell, a
       special program that runs each time Windows starts up.  In
       this configuration Take Command replaces the default Windows
       shell, Program Manager (see the online help or your Take
       Command Introduction and Installation Guide for details).


  Files and Directories

       You may have dozens, hundreds, or thousands of files stored
       on your computer's disks.  Your operating system is
       responsible for managing all of these files.  In order to do
       so, it uses a unique name to locate each file in much the
       same way that the post office assigns a unique address to
       every residence.

       The unique name of any file is composed of a drive letter, a
       directory path, and a filename.  Each of these parts of the
  -10-



       file's name is case insensitive; you can mix upper and lower
       case letters in any way you wish.


       Drives and Volumes

       A drive letter designates which drive contains the file.  In
       a file's full name, the drive letter is followed by a colon.
       Drive letters A: and B: are normally reserved for the floppy
       disk drives.

       Normally, drive C: is the first (or only) hard disk drive.
       Most current operating systems can divide a large hard disk
       into multiple logical drives or volumes that are usually
       called C:, D:, E:, etc.  Network systems (LANs) give
       additional drive letters to sections of the network file
       server drives.

       Most recent systems also include a CD-ROM drive.  The CD-ROM
       is also assigned a drive letter (or several letters, for CD-
       ROM changers), typically using letters beyond that used by
       the last hard disk in the system, but before any network
       drives.

       Some systems may have "RAM disks" (sometimes called "virtual
       disks"), which are areas of memory set aside by software (a
       "RAM disk driver") for use as fast but temporary storage.
       Like CD-ROM drives, RAM disks are usually assigned drive
       letters beyond the last hard disk in the system, but before
       network drives.

       For example, on a system with a large hard disk you might
       have A: and B: as floppy drives, C:, D:, and E: as parts of
       the hard disk, F: as a CD-ROM drive, G: as a RAM disk, and H:
       and I: as network drives.


       File Systems

       Each disk volume is organized according to a file system.
       The file system determines how files are named and how they
       are organized on the disk.

       As hard disk technology and operating systems have evolved,
       new file systems have been invented to support longer file
       names, larger drives, and higher disk performance.  Several
       different and incompatible schemes have evolved.  Which file
       systems you can use depend on which operating system you are
       using and how the operating system and your hard disk are
       configured.

       The operating systems under which our products run support
       five standard file systems:  FAT, VFAT, FAT32, HPFS, and
  -11-



       NTFS.  See File Names on page 14 for details on the rules for
       naming files under each file system.

            The FAT File System is the traditional file system used
            by all versions of DOS and by Windows 3.x.  Its name
            comes from the File Allocation Table DOS uses to keep
            track of the space allocated to each file.  Windows 95,
            Windows NT, and OS/2 also support the FAT file system.

            The VFAT File System is an extension of the FAT file
            system available in Windows 95 and Windows NT.  This
            system maintains additional information about files on
            FAT drives, including long filenames (LFNs).

            Other operating systems such as OS/2 and earlier
            versions of DOS can access files on VFAT drives, but
            will not be able to access long filenames or other
            information which is added by the VFAT file system.

            The FAT32 File System is an additional extension to the
            VFAT file system.  It is only available in Windows 95
            OEM Service Release 2 ("OEMSR2") and later versions.  It
            is similar to the VFAT file system, but supports larger
            disk drives.

            This file system is incompatible with OS/2, Windows NT,
            and earlier versions of DOS, and can only be used under
            Windows 95 OEMSR2.

            (If you are not sure whether your system is running
            Windows 95 OEM Service Release 2, use the Take Command
            VER /R command to check.  VER /R reports Windows 95 4.0
            build 950 for the original Windows 95 release, and build
            1111or higher for OEMSR2 and later versions.)

            The High Performance File System or HPFS is a file
            system provided with all versions of OS/2, and is also
            supported in Windows NT version 3.51 and below.  It
            supports long file names, and offers higher performance
            and better support for large drives than the FAT or VFAT
            system.  It also supports "extended attributes" (see
            page 17) to retain additional information about your
            files.

            DOS and Windows sessions running under OS/2 can access
            files on HPFS drives if the files have short, FAT-
            compatible names (see page 15).  Other operating systems
            (DOS, Windows 95, and Windows NT 4.0 and above) can not
            access files on HPFS drives.

            The Windows NT File System or NTFS is a file system
            provided with all versions of Windows NT.  Like HPFS,
            NTFS supports long file names and offers improved
            performance and support for large drives.  However, NTFS
  -12-



            does not support the "extended attributes" provided by
            HPFS.

            DOS programs running under Windows NT can access files
            on NTFS drives if the files have short, FAT-compatible
            names (see page 15).  Other operating systems (DOS and
            Windows 3.x, Windows 95, and OS/2) can not access files
            on NTFS drives.

       Throughout this manual, the term "LFN file system" is used to
       describe the VFAT and FAT32 systems as a group (LFN stands
       for Long File Name).

       Additional file systems may be installed under some operating
       systems to support CD-ROM or network drives.  In particular,
       OS/2 supports installable file systems, which are installed
       with the IFS= directive in the OS/2 CONFIG.SYS file.  This
       facility is used to add support for HPFS, CD-ROM, and network
       drives to the base OS/2 operating system.

       The file system type (FAT / VFAT, FAT32, HPFS, or NTFS) is
       determined when a hard disk volume is formatted and applies
       to the entire volume.  For example, you might have a 2 GB
       hard disk divided into four 500 MB volumes, with the first
       three volumes (C:, D:, and E:) formatted for the FAT or VFAT
       file system, and the fourth formatted for HPFS or NTFS.

       Take Command supports any standard file system installed
       under your operating system.  If your operating system can
       access files on a particular drive, then your version of Take
       Command will be able to access those files as well.


       Network File Systems

       A network file system allows you to access files stored on
       another computer on a network, rather than on your own
       system.  Take Command supports all network file systems which
       are compatible with the underlying operating system (Windows
       3.x, Windows 95, Windows NT, or OS/2).

       File and directory names for network file systems depend on
       both the "server" software running on the system that has the
       files on it, and the "client" software running on your
       computer to connect it to the network.  However, they usually
       follow the rules described here.

       Most network software "maps" unused drive letters on your
       system to specific locations on the network, and you can then
       treat the drive as if it were physically part of your local
       computer.

       Some networks also support the Universal Naming Convention,
       which provides a common method for accessing files on a
  -13-



       network drive without using a "mapped" drive letter.  Names
       specified this way are called UNC names.  They typically
       appear as \\server\volume\path\filename, where server is the
       name of the network server where the files reside, volume is
       the name of a disk volume on that server, and the
       path\filename portion is a directory name and file name which
       follow the conventions described under Directories below.
       Take Command supports UNC filenames, and also allows you to
       use UNC directory names when changing directories (see
       Directory Navigation on page 77 for more details).

       When you use a network file system, remember that the naming
       conventions for files on the network may not match those on
       your local system.  For example, your local system may
       support long filenames while the network server or client
       software does not, or vice versa.  Take Command will usually
       handle whatever naming conventions are supported by your
       network software, as long as the network software accurately
       reports the types of names it can handle.

       In some cases, Take Command (particularly Take Command/16)
       may not be able to report correct statistics on network
       drives (such as the number of bytes free on a drive).  This
       is usually because the network file system does not provide
       complete or accurate information.


       Directories and Subdirectories

       A file system is a method of organizing all of the files on
       an entire disk or hard disk volume.  Directories or folders
       are used to divide the files on a disk into logical groups
       that are easy to work with.  Their purpose is similar to the
       use of file drawers to contain groups of hanging folders,
       hanging folders to contain smaller manila folders, and so on.
       (The terms directory and folder are nearly synoymous -- we
       use directory throughout this manual.)

       Every drive has a root or base directory, and many have one
       or more subdirectories.  Subdirectories can also have
       subdirectories, extending in a branching tree structure from
       the root directory.  The collection of all directories on a
       drive is often called the directory tree, and a portion of
       the tree is sometimes called a subtree.  The terms directory
       and subdirectory are typically used interchangeably to mean a
       single subdirectory within this tree structure.

       Subdirectory names follow the same naming rules as files in
       each operating system (see below).  However, under DOS it is
       best to use a name of 8 characters or less, without an
       extension, when naming subdirectories, because some
       application programs do not properly handle subdirectory
       names that have an extension.
  -14-



       The drive and subdirectory portion of a file's name are
       collectively called the file's path.  For example, the file
       name C:\DIR1\DIR2\MYFILE.DAT says to look for the file
       MYFILE.DAT in the subdirectory DIR2 which is part of the
       subdirectory DIR1 which is on drive C.  The path for
       MYFILE.DAT is C:\DIR1\DIR2.  The backslashes between
       subdirectory names are required.

       The total length of a file's path may not exceed 64
       characters in DOS and Windows, and on FAT volumes under OS/2
       (this limit excludes the file name and extension, but
       includes the drive letter and colon).  On HPFS, NTFS, and LFN
       volumes, the path and file name must each be 255 characters
       or less in length, and in addition the total length of the
       path and file name together cannot exceed 260 characters.

       The operating system and command processor remember both a
       current or default drive for your system as a whole, and a
       current or default directory for every drive in your system.
       Whenever a program tries to create or access a file without
       specifying the file's path, the operating system uses the
       current drive (if no other drive is specified) and the
       current directory (if no other directory path is specified).

       The root directory is named using the drive letter and a
       single backslash.  For example, D:\ refers to the root
       directory of drive D:.  Using a drive letter with no
       directory name at all refers to the current directory on the
       specified drive.  For example, E:TCMD.DOC refers to the file
       TCMD.DOC in the current directory on drive E:, whereas
       E:\TCMD.DOC refers to the file TCMD.DOC in the root directory
       on drive E:.

       There are also two special subdirectory names that are useful
       in many situations:  a single period by itself [.] means "the
       current default directory."  Two periods together [..] means
       "the directory which contains the current default directory"
       (often referred to as the parent directory).  These special
       names can be used wherever a full directory name can be used.
       Take Command allows you to use additional periods to specify
       directories further "up" the tree (see page 91).


       File Names

       Finally, each file has a filename.  Under the FAT file
       system, the filename consists of a base name of 1 to 8
       characters plus an optional extension composed of a period
       plus 1 to 3 more characters.  Traditional FAT filenames with
       an 8-character name and a 3-character extension are sometimes
       referred to as short filenames (SFNs) to distinguish them
       from long filenames (LFNs).
  -15-



       You can use alphabetic and numeric characters plus the
       punctuation marks ! # $ % & ' ( ) - @ ^ _ ` { } and ~ in both
       the base name and the extension of a FAT filename.  Because
       the exclamation point [!], percent sign [%], caret [^], at
       sign [@], parentheses [()], and back-quote [`] also have
       other meanings to Take Command, it is best to avoid using
       them in filenames.

       The LFN, NTFS, and HPFS file systems, which can be used under
       Windows 95, Windows NT, and OS/2 allow file names with a
       maximum of 255 characters, including spaces and other
       characters that are not allowed in a FAT system file name,
       but excluding some punctuation characters which are allowed
       in FAT file names.  See your operating system documentation
       for details on the characters allowed.  If you use file names
       which contain semicolons [;], see page 94 for details on
       avoiding problems with interpretation of those file names
       under Take Command.

       FAT file names are always stored on the disk in upper case,
       and are displayed in upper or lower case depending on the
       options you select.  HPFS, NTFS, and LFN file names are
       stored and displayed exactly as you entered them, and are not
       automatically shifted to upper or lower case.  For example,
       you could create a file called MYFILE, myfile, or MyFile, and
       each name would be stored in the directory just as you
       entered it.  However, case is ignored when looking for
       filenames, so you cannot have two files whose names differ
       only in case (i.e., the three names given above would all
       refer to the same file).  This behavior is sometimes
       described as "case-retentive but not case-sensitive" because
       the case information is retained, but does not affect access
       to the files.

       Files stored on HPFS, NTFS, and LFN volumes often have "FAT-
       compatible" names:  names which contain only those characters
       legal on a FAT volume, and which meet the 8-character name /
       3-character extension limits.  Programs which cannot handle
       long names (for example, DOS programs accessing an HPFS drive
       under OS/2, or Windows 3 programs accessing an NTFS drive
       under Windows NT) generally can access files by using  FAT-
       compatible names.

       If an HPFS, NTFS, or LFN-compatible file name includes spaces
       or other characters that would not be allowed in a FAT name,
       you must place double quotes around the name.  For example,
       suppose you have a file named LET3 on a FAT volume, and you
       want to copy it to the LETTERS directory on drive F:, an HPFS
       partition, and give it the name Letter To Sara.  To do so,
       use either of these commands:

            [c:\wp] copy let3 f:\LETTERS\"Letter To Sara"
            [c:\wp] copy let3 "f:\LETTERS\Letter To Sara"
  -16-



       The HPFS, NTFS, and LFN file systems do not explicitly define
       an "extension" for file names which are not FAT-compatible.
       However, by convention, all characters after the last period
       in the file name are treated as the extension.  For example,
       the file name "Letter to Sara" has no extension, whereas the
       name "Letter.to.Sara" has the extension Sara.

       You may occasionally encounter filenames which are not
       displayed the way you expect if you have used characters from
       outside the U.S. English character set in the name.  These
       are generally due to problems in the way your operating
       system translates characters between the OEM and ANSI
       character sets.  Correcting the problem may require
       experimentation with fonts, character sets, and code pages,
       and occasionally some such problems may not be readily
       correctable within Take Command.  For more information on
       underlying issues related to fonts and character sets see
       page 23.


       File Attributes and Time Stamps

       Each file also has attributes and one or more time stamps.
       Attributes define characteristics of the file which may be
       useful to the operating system, to you, or to an application
       program.  Time stamps can record when the file was created,
       last modified, or last accessed.  Most Take Command file
       processing commands allow you to select files for processing
       based on their attributes and / or time stamp(s).

       Each file on your system has four standard attributes.  Every
       time a program modifies a file, the operating system sets the
       Archive attribute, which signals that the file has been
       modified since it was last backed up.  This attribute can be
       used by Take Command to determine which files to COPY or
       MOVE, and by backup programs to determine which files to back
       up.  When the Read-only attribute is set, the file can't be
       changed or erased accidentally; this can be used to help
       protect important files from damage.  The Hidden and System
       attributes prevent the file from appearing in normal
       directory listings.  (Two additional attributes, Directory
       and Volume label, are also available.  These attributes are
       controlled by the operating system, and are not modified
       directly by Take Command.)

       Attributes can be set and viewed with the ATTRIB command (see
       page 218).  The DIR command (see page 252) also has options
       to select filenames to view based on their attributes, to
       view the attributes themselves, and to view information about
       normally "invisible" hidden and system files.

       When a file is created, and every time it is modified, the
       operating system records the system time and date in a time
       stamp in the file's directory entry.  Several Take Command
  -17-



       variable functions and commands, and many backup and utility
       programs, use this time stamp to determine the relative ages
       of files.

       Files on HPFS, NTFS, and LFN volumes have three sets of time
       and date stamps.  The operating system records when each file
       was created, when it was last written or modified, and when
       it was last accessed.  The "last write" time stamp matches
       the single time stamp used on traditional FAT volumes.

       Several Take Command variable functions and commands let you
       specify which set of time and date stamps you want to view or
       work with on HPFS, NTFS, and LFN volumes.  These commands and
       functions use the letter "c" to refer to the creation time
       stamp, "w" for the last write time stamp, and "a" for the
       last access time stamp.  Note that LFN volumes, under both
       Windows 95 and Windows NT, store a date but no time in the
       "last access" time stamp; on these drives the time of last
       access will always be 00:00.


  OS/2 Extended Attributes

       The FAT and VFAT file systems allow the limited set of
       attributes for files described in the previous section.  OS/2
       supports additional information about files called "Extended
       Attributes" or "EAs."

       The Extended Attributes for a file provide additional
       information which is not part of the file's actual contents.
       This information might include the icon to be displayed for
       the file on the OS/2 desktop, or the type of data contained
       in the file.

       OS/2 supports Extended Attributes on both FAT and HPFS (High
       Performance File System) partitions.  EAs for the files on a
       FAT partition are stored in the file "EA DATA. SF" in the
       partition's root directory.  Like CMD.EXE, Take Command for
       OS/2 preserve a file's EAs when copying or moving the file,
       and OS/2 makes the appropriate adjustments to EAs when a file
       is deleted or renamed.

       When copying or moving a file from a FAT to an HPFS volume,
       Take Command uses uses the file's .LONGNAME EA, if available,
       for the HPFS filename.  Conversely, when copying or moving a
       file from an HPFS volume to a FAT volume, Take Command will
       set the .LONGNAME EA to the original HPFS name.  See the COPY
       and MOVE commands for additional details.

       If you boot DOS or any version of Windows, then delete or
       otherwise manipulate files that have Extended Attributes, you
       can face unexpected problems when you next boot under OS/2,
       because the EAs and directories will no longer be
       synchronized.  If you must manipulate files with Extended
  -18-



       Attributes during a DOS boot, or when you boot a "specific
       version of DOS" (not a standard DOS seesion) from OS/2, make
       sure you run OS/2's CHKDSK program to clean up any "orphaned"
       EAs.

       For more information on Extended Attributes, see your OS/2
       documentation.


  Internal and External Commands

       Whenever you type something at the Take Command prompt and
       press the Enter key, you have given a command, and Take
       Command must figure out how to execute it.  If you understand
       the general process that Take Command uses, you will be able
       to make the best use of it and its commands.

       Take Command begins by dividing the line you typed into a
       command name and a command tail.  The command name is the
       first word in the command; the tail is everything that
       follows the command name.  For example, in this command line:

            dir *.txt /2/p/v

       the command name is "dir", and the command tail is " *.txt
       /2/p/v."

       If the command name is not an alias (see page 113) or, in
       Take Command/32, an Internet URL beginning with http: (see
       page 73), Take Command tries to find the name in its list of
       internal commands.  An internal command is one that Take
       Command can perform itself, without running another program.
       DIR and COPY are examples of internal commands.

       If the command name is not found in Take Command's list of
       internal commands, it assumes that it must find and execute
       an external command.  This means that it must load and run a
       separate program, either an executable program or a batch
       file.  DOS, OS/2, and Windows are shipped with a number of
       external utility programs (such as FORMAT and DISKCOPY), and
       any program or application you install on your system becomes
       a new external command.

       The advantage of internal commands is that they run almost
       instantly.  When you type an internal command, Take Command
       interprets the command line and carries out the necessary
       activities without having to look for, load, and run another
       program.

       The advantage of external commands is that they can be large,
       varied, and complex without taking space inside Take Command.
       External commands can also be renamed or replaced easily.  If
       you want to rename the external DOS command XCOPY to MYCOPY,
       for example, all you need to do is find the file called
  -19-



       XCOPY.EXE in your DOS or Windows/Command directory and change
       its name to MYCOPY.EXE.  If you want to replace XCOPY with a
       more efficient program of the same name, you can do so.  Take
       Command adds this flexibility to internal commands.  You can
       rename or replace any internal command by using an alias (see
       pages 113 and 206), and you can enable or disable internal
       commands whenever you wish (see SETDOS /I on page 386).


  Executable Files and File Searches

       Once Take Command knows that it is supposed to run an
       external command, it tries to find an executable file whose
       name matches the command name.  (Executable files are
       typically those with a .COM or .EXE extension, or with a .PIF
       extension under Windows.)  It runs the executable file if it
       finds one.  (See the previous section for more information on
       external commands.)

       If Take Command cannot find an executable program to run, it
       next looks for a batch file (a file with one or more commands
       in it) whose name matches the command name.  Take Command
       looks first for a .BTM file, then for a .CMD file (in Take
       Command/32 and Take Command for OS/2), then for a .BAT file,
       and finally for a .REX file (in Take Command/32 running under
       Windows NT)  See page 116 for more information on these
       different types of batch files.  If the command processor
       finds such a file, it then reads each line in the file as a
       new command.

       If the search for a batch file fails, Take Command checks to
       see if the command name matches the name of a file with an
       extension that is associated with a specific application (for
       example, if you have associated .DOC with your editor or word
       processor, and type the name of a .DOC file).  If a match is
       found, Take Command runs the program specified when the
       association was defined.

       In searching for the application associated with a file, Take
       Command will first examine any executable extensions you have
       defined (an executable extension associates a file extension
       with a specific program to process that type of file; see
       page 102 for details).  Take Command then checks file
       associations defined in WIN.INI and / or the Windows
       registry; see the next section for complete details.

       Take Command first searches for an executable program, a
       batch file, or a file with an executable extension or Windows
       file association in the current directory.  If that search
       fails, it repeats its search in every directory in your
       search path.

       The search path is a list of directories that Take Command
       (and some applications) search for executable files.  For
  -20-



       example, if you wanted Take Command to search the root
       directory of the C: drive, the \WINUTIL subdirectory on the
       C: drive, and the \UTIL directory on the D: drive for
       executable files, your search path would look like this:

            PATH=C:\;C:\WINUTIL;D:\UTIL

       Notice that the directory names in the search path are
       separated by semicolons.

       You can create or view the search path with the PATH command
       (see page 351).  You can use the ESET command (see page 283)
       to edit the path.  Many programs also use the search path to
       find their own files.  The search path is stored in the
       environment with the name PATH.

       Take Command/16 also searches the \WINDOWS and
       \WINDOWS\SYSTEM directories, in that order, after the current
       directory and before any directories listed in your search
       path.  Similarly, under Windows 95, Take Command/32 searches
       the \WINDOWS directory then the \WINDOWS\SYSTEM directory;
       under Windows NT the order is reversed, and Take Command/32
       searches the \WINDOWS\SYSTEM32 directory followed by the
       \WINDOWS directory.  (The actual directory names may be
       different on your system.  Take Command will determine the
       correct names for the "Windows" and "Windows System"
       directories and use them.)  These search procedures conform
       with the traditional search sequences used under each
       operating system (Windows, Windows 95, and Windows NT).  Take
       Command for OS/2 does not use special search sequences of
       this type; all directories to be searched must be explicitly
       listed in the PATH.

       Remember, Take Command always looks for an executable file
       (or a file with an executable extension or Windows file
       association) in the current subdirectory, then in the Windows
       directories if appropriate (see above), and then in each
       directory in the search path.  (You can change the search
       order so the current directory is not searched first; see the
       PATH command for details.)

       If you include an extension as part of the command name, Take
       Command only searches for a file with that extension.
       Similarly, if you include a path as part of the command name,
       Take Command will look only in the directory you specified,
       and ignore the usual search of the current directory and the
       PATH.

       The following table sums up the possible search options (the
       term "standard search" refers to the search of the current
       directory, the Windows directories in Take Command/16 and
       Take Command/32, and each directory in the search path):

            Command           Take Command Search Sequence
  -21-



            -------           ----------------------------

            WP                Standard search for any executable
                              file whose base name is WP.

            WP.EXE            Standard search for WP.EXE; will not
                              find files with other extensions.

            C:\WP7\WP         Looks in the C:\WP7 directory for any
                              executable file whose base name is WP.
                              Does not check the standard search
                              directories.

            C:\WP7\WP.EXE     Looks only for the file C:\WP7\WP.EXE.

            LAB.DOC           Standard search for LAB.DOC, if .DOC
                              is defined as a Take Command
                              executable extension or Windows file
                              association.  Runs the associated
                              application if the file is found.

            C:\LI\LAB.DOC     Looks only for the file C:\LI\LAB.DOC,
                              and only if .DOC is defined as a Take
                              Command executable extension or
                              Windows file association.  Runs the
                              associated application if the file is
                              found.

       If Take Command cannot find an executable file, batch
       program, or a file with an executable extension or Windows
       file association in the current directory, a directory in the
       search path, or the directory you specified in the command,
       it then looks for an alias called UNKNOWN_CMD (see ALIAS on
       page 206 for details).  If you have defined an alias with
       that name, it is executed (this allows you to control error
       handling for unknown commands).  Otherwise, Take Command
       displays an "Unknown command" error message and waits for
       your next instruction.


TC16,  Windows File Associations
TC32

       Windows 3.x, Windows 95, and Windows NT include the ability
       to associate file extensions with specific applications; this
       feature is sometimes called "file associations".  For
       example, when you install Microsoft Word, it creates an
       association between files with a .DOC or .DOT extension and
       the Word program file, WINWORD.EXE.

       Take Command includes a similar feature, called "executable
       extensions," which allows you to set environment variables
       which associate a file extension with a particular
       application (see page 102 for complete details).
  -22-



       Under Windows 3.x file associations can be stored in two
       places:  the WIN.INI file, and the Windows registry.
       Associations in WIN.INI are "direct" -- they simply list the
       extension and the application name, associating the extension
       directly with the application.  Those in the registry are
       "indirect" -- they associate an extension with a "file type,"
       and separately specify attributes of files of that type,
       including the command to execute in order to open such a
       file.

       Windows 95 and Windows NT maintain a similar structure,
       although both the "direct" and "indirect" associations are
       typically stored in the registry.

       When Take Command starts, it retrieves the direct file
       associations from Windows, and treats them like Take Command
       executable extensions.  To disable loading of these direct
       associations see the Startup page of the configuration
       dialogs, or the LoadAssociations directive in the .INI file.
       The indirect associations are accessed through built-in
       Windows features (see below), and can not be disabled.

       When you attempt to execute a program from the command line
       or a batch file, Take Command first searches its list of
       executable extensions, including the standard extensions
       (.COM, .EXE, .BTM, etc.).  It then checks Take Command
       executable extensions, followed by direct file associations
       inherited from Windows.  If  all of these tests fail, Take
       Command passes the command name to Windows to see if Windows
       can find an indirect association for it.  Each of these tests
       is done in all of the standard search directories described
       in the previous section.

       See Using Windows File Associations on page 105 for
       additional details on how to control Windows file
       associations in Take Command, including dealing with
       conflicts between direct and indirect associations.  Also see
       the ASSOC and FTYPE commands (pages 217 and 302).


  The Environment

       The operating system allows you to keep a list of information
       in memory.  This list is called the environment.  Every
       program receives a copy of the environment when it begins,
       and many programs use some of its information to configure
       themselves or to find files.

       The environment is arranged as a series of variables and
       their related values.  Each variable consists of a name
       followed by an equal sign [=] and some text (the value).  For
       compatibility with traditional command processors, Take
       Command/16 and Take Command for OS/2 store the variable name
       in upper case, regardless of how you enter it.  Like Windows
  -23-



       NT's CMD.EXE, Take Command/32 stores the name as you enter
       it, and does not shift it to upper case (however, case is
       ignored when looking for a variable; for example MyVar,
       myvar, and MYVAR all refer to the same variable).

       You can view the environment by typing SET, and add new
       entries or edit existing entries with the SET and ESET
       commands.  You can erase entries in the environment with both
       the UNSET and SET commands.

       A typical environment entry looks like this:

            LIB=c:\lib

       In this example, the name of the variable is "LIB" and its
       value is "c:\lib".  The text string or value can include any
       character except a null (ASCII 0).

       The format and meaning of each entry in the environment is up
       to the program that uses the particular variable.
       Environment variables can contain just about anything, and
       can be used for any purpose the author of a program desires.
       The "purpose" of the environment as a whole is simply to hold
       small amounts of text which programs can then access
       according to their own rules.  Most environment variables are
       used by single programs for their own information; a few
       (like PATH) have well-defined meanings and are used by many
       different programs.

       Take Command uses several environment variables to control
       its own behavior.  It also provides a wide range of
       facilities for manipulating and managing the environment.
       See "Using the Environment" beginning on page 137 for details
       about these special variables, the size of the environment,
       and other environment-related features.

TC16   By default, when you use Take Command/16 to start a Windows
       program, that program receives a copy of the Windows startup
       environment without any changes made from within Take
       Command.  DOS applications that are run under Caveman (see
       your Introduction and Installation Guide) always receive Take
       Command's version of the environment; those that are run with
       the START command always receive the Windows startup
       environment.  You can alter this default behavior somewhat by
       using the START /E command to start Windows and DOS
       applications; see page 394 for details.


  Character Sets, ASCII, and Key Codes

       The translation of a key you type on the keyboard to a
       displayed character on the screen depends on several related
       aspects of character handling.  A complete discussion of
       these topics is well beyond the scope of this manual.
  -24-



       However, a basic picture of the steps in the keystroke and
       character translation process will help you understand how
       characters are processed in your system, and why they
       occasionally may not come out the way you expect.

       Internally, computers use numbers to represent the keys you
       press and the characters displayed on the screen.  To display
       the text that you type, your computer and operating system
       require five pieces of information:

            *  The numeric key code for the physical key you
               pressed;

            *  The specific character that key code represents based
               on your current keyboard layout or country setting;

            *  The character set currently in use on your system
               (see below);

            *  The international code page in use for that character
               set; and

            *  The display font used to display the character.

       The numeric key code is determined by your physical hardware
       including the language that your keyboard is produced for.
       The character set is usually determined by the operating
       system.  These items typically are not under your control.
       However, most systems do allow you to control the keyboard
       country setting, the code page, and the display font.

       If the key codes produced by your keyboard, the code page,
       and the font you choose are not fully compatible with each
       other, the characters displayed on the screen will not match
       what you type.  The differences are likely to appear in line-
       drawing characters, "international" (non-English) characters,
       and special symbols, not in commonly-used U.S. English
       alphabetic, numeric, or punctuation characters.

       Most systems use a "single-byte" character set for keyboard
       and screen display.  These sets define 256 characters or
       symbols, with a numeric representation for each.  ("Double-
       byte" character sets, with up to 65,536 characters each, are
       used for languages with more than 256 symbols, and for some
       multi-lingual systems.)  Most PC single-byte character sets
       are based on a code called ASCII, the American Standard Code
       for Information Interchange.

       The original ASCII code was defined over 30 years ago for use
       in mainframe and minicomputer systems, and has 128 character
       values.  These include the upper and lower case letters,
       numerals, and punctuation marks used in U.S. English, plus
       non-printing control codes (which can be entered on most
       keyboards by pressing the Ctrl key plus another character, or
  -25-



       by pressing certain special keys like Tab, Enter, Backspace,
       and Esc).  However, ASCII is not a complete character set,
       because it defines only 128 of the required 256 symbols.

       IBM, in its original PC, created a complete 256-character set
       (called the Original Equipment Manufacturer or "OEM"
       character set) by defining an additional 128 extended ASCII
       codes for math symbols, "international" characters, the
       characters used to draw boxes and lines, and some
       miscellaneous symbols.

       Some operating systems support other character sets; in
       particular, Windows uses the ANSI character set internally to
       store and display text, even though other parts of the system
       (e.g. the file system which stores file names on disk) use
       IBM's OEM character set.  The ANSI character set is identical
       to the OEM character set for U.S. English printed characters,
       but may vary for "international" characters not used in U.S.
       English.  In most cases, Windows automatically translates
       characters from one set to another as needed, but problems
       can sometimes result in errors in displayed text (e.g.,
       differences between the appearance of accented characters in
       filenames in Windows and DOS applications).

TCOS2  Under OS/2, the code page you define for use on your system
       represents a variation of the character set.  Most code pages
       define the standard ASCII characters for the 128 codes in the
       first half of the character set, and select different
       characters for codes in the second half of the set.  These
       variations usually provide for necessary international
       symbols.  Code pages have numbers, and also have names which
       reflect the country whose character set they contain; for
       example, code page 437 is entitled "MS-DOS United States",
       code page 865 is entitled "MS-DOS Nordic", and so on.

       See your operating system documentation for more information
       about character sets, code pages, and country and language
       support.

       The Take Command online help system has complete tables of
       standard ASCII and key codes.  Refer to your operating system
       and / or font documentation for details on the full character
       set available in any particular font.


  The Keyboard

       When you press or release a key on the keyboard, Windows and
       OS/2 intercept the keystroke and interpret its meaning.  Most
       keystrokes are translated into messages which are sent to the
       application that has the "focus," that is, to the program
       whose window is highlighted.  Some keystrokes and key
       combinations, such as Alt-Tab in Windows, are interpreted by
       the operating system as direct commands to perform such
  -26-



       actions as changing the focus to a new program, copying the
       current window to the clipboard, etc.

       Windows and OS/2 always interpret Alt plus a key as a menu
       accelerator keystroke.  Such keystrokes are not passed to
       Take Command.  Therefore, Alt-key combinations cannot be used
       for aliases and other special uses in Take Command.

       When the operating system sends a keystroke to Take Command,
       it arrives as a combination of an ASCII code and a scan or
       keyboard code.  The online help has a complete list of ASCII
       and scan codes for the keys on most keyboards.
