When an application exits, if the transient portion of the command interpreter in memory was overwritten, DOS will reload it from disk.
In DOS 6, these were replaced by commercial programs (CPBACKUP, MSBACKUP), which allowed files to be restored to different locations.
BASICA last appeared in IBM PC DOS 5.02, and in OS/2 (2.0 and later), the version had ROM-BASIC moved into the program code.
This command is used to instruct DOS to check whether the Ctrl and Break keys have been pressed before carrying out a program request.
[1] The CHDIR (or the alternative name CD) command either displays or changes the current working directory.
[1] (Not a command: This is a batch file added to DOS 6.X Supplemental Disks to help create DoubleSpace boot floppies.
In Windows NT, the functionality provided exists but is handled by the command rd or rmdir which has slightly different syntax.
The resulting directory listing can be sorted by various criteria and filenames can be displayed in a chosen format.
[1] The ECHO command prints its own arguments back out to the DOS equivalent of the standard output stream.
The size of the resident code and data sections combined in the input .exe file must be less than 64 KB.
The name derives from IBM's habit of calling hard drives fixed disks.
MemMaker would then calculate the optimal Driver and TSR placement in upper memory and modify the AUTOEXEC.BAT and CONFIG.SYS accordingly, and reboot the second time.
The MIRROR command saves disk storage information that can be used to recover accidentally erased files.
[1] MSCDEX is a driver executable which allows DOS programs to recognize, read, and control CD-ROMs.
[22] Loads extended Nationalization and Localization Support from COUNTRY.SYS, and changed the codepage of drivers and system modules resident in RAM.
[citation needed] In later versions of DR-DOS 6, NLSFUNC relocated itself into the HiMem area, thereby freeing a portion of the nearly invaluable lower 640KiB that constituted the ”conventional” memory available to software.
[1] Suspends processing of a batch program and displays the message Press any key to continue.
A primitive filesystem error recovery utility included in MS-DOS / IBM PC DOS.
[1] Its primary advantages over chkdsk is that it is more reliable and has the ability to run a surface scan which finds and marks bad clusters on the disk.
It also provided mouse point-and-click TUI, allowing for interactive session to complement command-line batch run.
chkdsk had surface scan and bad cluster detection functionality included, and was used again on Windows NT-based operating systems.
The SELECT command formats a disk and installs country-specific information and keyboard codes.
The version included with MS-DOS 4 and PC DOS 4 is no longer a simple command-line utility, but a full-fledged installer.
[1] cmd.exe in Windows NT 2000, 4DOS, 4OS2, 4NT, and a number of third-party solutions allow direct entry of environment variables from the command prompt.
From at least Windows 2000, the set command allows for the evaluation of strings into variables, thus providing inter alia a means of performing integer arithmetic.
[1] The SHIFT command increases number of replaceable parameters to more than the standard ten for use in batch files.
SYS does not rewrite the Master Boot Record, contrary to widely held belief.
[1] Internal command that expands the name of a file, directory, or drive, and display its absolute pathname as the result.
By default all recoverable files in the working directory are restored; options are used to change this behavior.
If the MS-DOS mirror TSR program is used, then deletion tracking files are created and can be used by undelete.