Information About4dos |
| CATEGORIES ABOUT 4DOS | |
| dos on ibm pc compatibles | |
| command shells | |
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name = 4DOS
4DOS is a Command Line Interpreter by JP Software, designed to replace the default command interpreter COMMAND.COM inDOS and Windows 95 / 98 / Me . Related products that substitute for Windows NT 's command interpreter ( 4NT ) and IBM's OS/2 command interpreter (4OS2) are also available. 4DOS was written by Rex Conn and Tom Rawson; it was first released in 1989 . FEATURES 4DOS features a number of enhancements when compared to COMMAND.COM:
HISTORY AND CURRENT STATUS Originally distributed as Shareware , the now obsolete 4DOS has been released as unsupported Freeware . The last update was version 7.50.130, released in August 2004 . During its 15-year history, 4DOS underwent numerous updates; here are a few of the most significant. Some versions of the Norton Utilities for DOS included modified copies of 4DOS called NDOS. The last version of NDOS was bundled with Norton Utilities 8, and corresponded to 4DOS 4.03. 4DOS STARTUP As a DOS command shell intended to replace the default COMMAND.COM , 4DOS is typically installed via aSHELL directive in CONFIG.SYS . However, itcan also be launched by any method used to run Executable programs: typing its filename at a command line or in the Windows Start /Run Dialog , double-clicking on a Windows Shortcut icon, and so on. See the Allenware guide listed under External Links for one approach to using 4DOS as a secondary shell, and as an external helper for COMMAND.COM batch files.4DOS may be passed various Switches (options) in its command tail. Most of COMMAND.COM's startup switches aresupported, including /P (primary shell), '''/E:''' (environment size), and /C and '''/K''' (execute a command.) There are also several new options, most notably @ specify the location of the .INI File and // it were present in the .INI file. Most of 4DOS's configuration is stored in an .INI file. There are well over 100 directives available, controlling everything from display colors and key bindings to technical details of memory allocation. This file is named 4DOS.INI by default, and is usually in the samedirectory as the 4DOS.COM binary. Three sections aresignificant: {Link without Title} applies to all instances of 4DOS, {Link without Title} applies only to the first instance of 4DOS loaded into memory, and {Link without Title} only to other instances. Sections other than '''[Primary ''' and '''[Secondary]''' are ignored. After the .INI file is processed 4DOS looks for a startup Batch File , typically named 4START.BTM or 4START.BAT and inthe same location as 4DOS.COM, and runs it if found. Thisfile corresponds, more or less, to the .bashrc script used byBash . (4DOS can also run a 4EXIT.BTM or4EXIT.BAT batch file when it exits, making it possible toautomatically save the Command History or the directory history to a file on exit and reload it on the next run.) If 4DOS is the primary shell (i.e. started with the /P switch), AUTOEXEC.BAT will be run after any4START. The names and locations of all theseautomatically-run batch files may be redefined via .INI directives. INTERNAL COMMANDS These are the internal commands provided by 4DOS 7.50, with a brief description of what each is used for. Commands are not case-sensitive. File management and directory navigation ; ''d ; ''dirname\'' : (directory name ending with a backslash) Make the specified directory current; implied CDD ; ATTRIB : Display or change file and directory attributes ; CD or CHDIR : Display or change the current Working Directory ; CDD : Change current drive and directory ; COPY : Copy files and directories ; DEL or ERASE : Delete files ; DESCRIBE : Change file descriptions ; DIR : List files and subdirectories ; DIRHISTORY : Display or change the directory history ; DIRS : Display the directory Stack ; EXCEPT : Temporarily hide files from another command ; FFIND : Find files ; FREE : Display free space on drives ; GLOBAL : Recursively visit subdirectories for the benefit of an external command ; HEAD : Display the specified number of lines from the start of a text file ; LIST : Display a text file ; MD or MKDIR : Create subdirectories ; MOVE : Move files from one location to another ; POPD : Restore a saved drive and directory from the directory stack ; PUSHD : Save the current drive and directory on a stack; optionally change directories ; RD or RMDIR : Remove subdirectories ; REN or RENAME : Rename files or subdirectories ; SELECT : Interactively select files for another command ; TAIL : Display the specified number of lines from the end of a text file ; TOUCH : Change date and time stamps of files ; TREE : Display a subdirectory hierarchy ; TRUENAME : Display a canonicalized filename, resolving JOIN and SUBST, network drive mappings, etc. ; TYPE : Dump text files to standard output ; VOL : Display volume labels Input, output, and user interaction ; BEEP : Make a sound ; CLS : Clear the screen ; COLOR : Change the display colors ; DELAY : Pause for a specified time ; DRAWBOX : Draw a rectangle ; DRAWHLINE : Draw a horizontal line ; DRAWVLINE : Draw a vertical line ; ECHO : Output text to Standard Output ; ECHOERR : Output text to Standard Error ; ECHOS : Output text to Standard Output without appending an End-of-line ; ECHOSERR : Output text to Standard Error without appending an End-of-line ; HEAD : Display the specified number of lines from the start of a text file ; INKEY : Accept a keystroke from the user ; INPUT : Accept a string from the user ; LIST : Display a text file ; PAUSE : Wait for a keystroke from the user ; SCREEN : Position the screen cursor, and optionally display a message ; SCRPUT : Display a message on screen with a specific location and color ; SELECT : Interactively select files for another command ; TAIL : Display the specified number of lines from the end of a text file ; TEE : Split Standard Input to Standard Output and a file ; TEXT : Display a block of lines in a batch file ; TYPE : Dump text files to standard output ; Y : Combine Standard Input and files to Standard Output Conditional and flow-control commands ; '' ; ? : List internal commands, or prompt before executing a command ; CALL : Start another batch file like a subroutine; resume after the CALL when it exits ; CANCEL : Abort all batch file processing ; DO : Multiline loop structure for batch files ; EXIT : Terminate the current shell, unless it is the primary shell ; FOR : Single-line loop structure ; GOSUB : Execute a labelled subroutine within a batch file ; GOTO : Jump to a label within a batch file ; IF : Execute a command conditionally ; IFF : Execute a block of commands conditionally ; ON : Enable or disable error handling in a batch file ; QUIT : End processing of the current batch file ; REM : Disregard the remainder of the line as a remark or Comment ; RETURN : End a subroutine, and continue with the command after GOSUB ; SWITCH : Execute a block of lines according to the value of an expression Other commands ; ? : List internal commands, or prompt before executing a command ; ALIAS : Define or list aliases ; BREAK : Show or change DOS Control-C and Control-Break checking status ; CHCP : Display or change the current DOS code page ; CTTY : Change the DOS console device ; DATE : Display or change the system date ; ESET : Edit the contents of an Environment Variable ; FUNCTION : Create or list user-defined functions ; HISTORY : Display or change the command history ; HELP : Launch the online help system ; KEYBD : Display or change the keyboard toggles ; KEYSTACK : Stack keystrokes for use by another program ; LFNFOR : Enable or disable return of long filenames in FOR ; LH or LOADHIGH : Load a program into Upper Memory ; LOADBTM : Control caching of batch files to memory ; LOCK and UNLOCK : Enable and disable low-level drive access in Windows 95 / 98 / Me ; LOG : Control logging of commands to a text file ; MEMORY : Display usage of DOS memory ; OPTION : Interactively configure 4DOS ; PATH : Display or change the search path ; PROMPT : Change the command prompt ; REBOOT : Restart the computer ; SET : Display or change environment variables ; SETDOS : Change various configuration settings ; SETLOCAL and ENDLOCAL : Save and restore the environment, aliases, current directory, and other settings ; SHIFT : Step through batch file parameters ; START : (OS/2 only) Execute a command in another session ; SWAPPING : Display or change 4DOS disk/memory swapping setup ; TIME : Display or change the system time ; TIMER : Control or display 4DOS internal timers ; UNALIAS : Undefine command aliases ; UNFUNCTION : Undefine user functions ; UNSET : Undefine environment variables ; VER : Display version strings for 4DOS and DOS ; VERIFY : Display or change the DOS write-verify flag ; VSCRPUT : Display text vertically ; WHICH : Display location of a command VARIABLES Environment variables A copy of the environment is inherited by all programs started from 4DOS, including new instances of 4DOS. In a batch file, the environment may be saved and restored using the SETLOCAL and ENDLOCAL commands. Environment variable names should preferentially be composed only of alphanumerics, underscores, and dollar signs, and should not begin with a digit. Other names are possible using the bracket syntax, below. Environment variables are referenced by enclosing the variable name in percent signs: echo %colordir% The closing percent sign maybe omitted if this does not create an ambiguity for the parser. Strange variable names containing troublesome characters or nested variables may be referenced by putting the variable name in brackets with no closing percent sign:
The following environment variables have special significance to 4DOS: ; _CDPATH , CDPATH : Used for directory searches (checked in this order) ; CMDLINE : Contains the current command line ; COLORDIR : Used for directory colorization (overrides .INI directive) ; COMSPEC : Complete pathname of the current shell ; DOSHELP : Pathname of external DOS help utility ; FILECOMPLETION : Used for filename completion ; LOGINNAME : User name ; PATH : Search path ; PATHEXT : Extension search order ; PROMPT : Used to display the interactive prompt ; TEMP4DOS, TEMP, TMP : Used for temporary and pipe files (checked in this order) ; TITLEPROMPT : Used to customize the title bar in Windows 95/98/Me Internal variables 4DOS implements over 60 internal variables, which are referenced like environment variables (with a leading percent sign) but are not stored in the environment block. Like environment variables, internal variables are evaluated before the command is executed, so they may be used with external commands as well as internal commands. The following list is not complete. ; %? : Return code of the last external program ; %_? : Return code of the last internal command ; %+ : Current command separator character ; %= : Current syntactic escape character ; %_4VER : 4DOS version ; %_ALIAS : Free alias space (bytes) ; %_ANSI : ANSI driver detected? ; %_BATCHLINE : Line number in the current batch file ; %_BATCHNAME : Complete filename of the current batch file ; %_BG : Background color under the cursor ; %_BOOT : Drive from which DOS was booted ; %_COLUMN : Current cursor horizontal position ; %_CPU : Processor type ; %_CWD : Current drive and directory ; %_CWP : Current directory ; %_DATE : Current date, in the local date format ; %_DISK : Current drive letter ; %_DOSVER : Returns the DOS version ; %_ENV : Free environment space (bytes) ; %_FG : Foreground color at the cursor ; %_ISODATE : Current date in ISO format ; %_LASTDISK : DOS LASTDRIVE value ; %_MOUSE : Mouse driver detected? ; %_ROW : Current cursor vertical position ; %_SHELL : Shell nesting level ; %_TIME : Current time, in the local time format ; %_WIN : Microsoft Windows detected? Variable functions Variable functions are referenced much like internal or environment variables, with a leading percent sign. Unlike variables, however, they take one or more arguments, somewhat like functions in a Programming Language . Variable function arguments are enclosed in square brackets. Variable functions are expanded before the command is executed, so they can be used with both internal and external commands. 4DOS supports over 100 variable functions; the following list is not complete. ; %@ASCII {Link without Title} : Returns values of characters ; %@ATTRIB {Link without Title} : Return a file's attributes ; %@CDROM {Link without Title} : Is drive ''d:'' a CD-ROM? ; %@CHAR {Link without Title} : ASCII character with value ''n'' ; %@CRC32 {Link without Title} : Computes CRC32 checksum ; %@DATE {Link without Title} : Converts a calendar date to a DOS day number, January 1 , 1980 being 0. ; %@DEC {Link without Title} : Returns ''n'' minus 1 |
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