Unlike the Registry the Environment is local to and specific for each
running process. This contains NAME-VALUE pairs and variables are
case-dependent. When a process is started it inherits the Environment
from its parent.
The System uses certain Environment variables to convey information.
Applications are free to use environment variables to pass parameters
or to temporarily store state information.
The SET command is used to view and define environment content.
The backspace key has a different usage on Linux based systems.
The command line process attempts to detect the intended use and
when it does sets the BKSP variable. A value of '1' indicates that
the connecting terminal is Windows based or otherwise uses the
This holds the Current Directory. The current working directory is
also displayed as the command line prompt. File paths not beginning
with the path separator '/' are relative to the current directory.
Contains the command line used to execute an program. The parent
process stores the command line here, executes the application and
then removes it. A program can retrieve the command line used to start
Defines the display width in characters. The default and minimum
is 80. This is used in formatting output from commands such as
HELP and DIR.
Programs generally return a numeric result. This is typically zero '0'
upon successful completion. The returned value can be used as an error
code or other purpose. The returned value is placed in the ERRORLEVEL
These variables are set when an application has been started using
a Run/ Registry Key. Application programs can be started at boot
using these keys. RUNKEY provides the key name. RUNCMD holds the
key value which would be the command line command starting the
Environment variables can be referenced by commands in batch files.
A variable name surrounded by percent '%' signs in a batch command
line are replaced with the value of the variable.
HELP Topics: SETENV