Environment Variable

Small piece of data used to store values for software
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Wikipedia creation date
10/25/2003
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An environment variable is a dynamic-named value that can affect the way running processes will behave on a computer. They are part of the environment in which a process runs. For example, a running process can query the value of the TEMP environment variable to discover a suitable location to store temporary files, or the HOME or USERPROFILE variable to find the directory structure owned by the user running the process. They were introduced in their modern form in 1979 with Version 7 Unix, so are included in all Unix operating system flavors and variants from that point onward including Linux and macOS. From PC DOS 2.0 in 1982, all succeeding Microsoft operating systems including Microsoft Windows, and OS/2 also have included them as a feature, although with somewhat different syntax, usage and standard variable names.
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%SystemRoot%
%SystemDrive%
C:\WINDOWS
Environment variables
Env var
LC ALL
Environment (computing)
Shell variable
Printenv
AppData
Environmental variable
%SYSTEMROOT%
$HOME
System variable
LD LIBRARY PATH
LIBPATH
LIBPATH (AIX)
PROMPT (environment variable)
Master environment
Pre-environment
Reserved environment variable
Master environment variable
Local environment variable
Local environment (computing)
Local environment (DOS)
Master environment (DOS)
Pre-environment variable
Environment segment
Environment segment (computing)
Environment segment (DOS)
%APPEND%
%CONFIG%
%CMDLINE%
%COMSPEC%
%COPYCMD%
%DIRCMD%
%LANG%
%LANGSPEC%
%NO SEP%
%PATH%
%PROMPT%
%TEMP%
%TMP%
System environment
System environment (computing)
System environment (DOS)
System information variable
System information variable (computing)
System information variable (DOS)
$CLS (environment variable)
Pseudo-environment variable
Unix environment variable
DOS environment variable
GEM environment variable
OS/2 environment variable
Windows environment variable
DOS pseudo-environment variable
Windows pseudo-environment variable
Dynamic environment variable
Dynamic environment variable (Microsoft)
Dynamic environment variable (Windows)
Dynamic environment variable (CMD)
Dynamic environment variable (COMMAND.COM)
Dynamic environment variable (DOS)
System info variable
System information variable (COMMAND.COM)
DOS system information variable
DOS system info variable
Internal variable (4DOS)
Internal variable (4OS2)
Internal variable (4NT)
Internal variable (JP Software)
4DOS internal variable
4OS2 internal variable
4NT internal variable
4DOS variable function
4OS2 variable function
4NT variable function
Variable function (4DOS)
Variable function (4OS2)
Variable function (4NT)
Variable function (JP Software)
JP Software variable function
JP Software internal variable
Dynamic environment variable (COMMAND)
System information variable (COMMAND)
DR-DOS system information variable
Novell DOS system information variable
Novell system information variable
OpenDOS system information variable
Caldera system information variable
RETURN (DOS command)
%DRDOSCFG%
%NWDOSCFG%
%OPENDOSCFG%
%DRCOMSPEC%
%DRSYS%
%HOMEDIR%
%CMDCMDLINE%
%CMDEXTVERSION%
%RANDOM%
%TIME%
%SWITCHAR%
%PEXEC%
%OS%
%NOSOUND%
%NOCHAR%
%LOGINNAME%
%INFO%
%$DIR%
%$PAGE%
%$LENGTH%
%$WIDTH%
%VER%
%YESCHAR%
%$CLS%
%TASKMGRWINDIR%
%$SLICE%
%$ON%
%$OFF%
%$HEADER%
%$FOOTER%
%ERRORLEVEL%
%ERRORLVL%
%HOUR%
%HOUR24%
%MINUTE%
%MONTH%
%SECOND%
%YEAR%
%/%
%STATION%
%MDOS EXEC%
%AM PM%
%GREETING TIME%
%MONTH NAME%
%NDAY OF WEEK%
%OS VERSION%
%SHORT YEAR%
%LOGIN NAME%
%P STATION%
%FULL NAME%
% YEAR%
% CODEPAGE%
% COLUMNS%
% COUNTRY%
% DAY%
% HOUR%
% MINUTE%
% MONTH%
% ROWS%
% SECOND%
MS-DOS environment
FBP USER (environment variable)
FBP USER
BEGINLIBPATH (environment variable)
BEGINLIBPATH
ENDLIBPATH (environment variable)
ENDLIBPATH
Unset (Unix)
C\WINDOWS
System variables
CD (pseudo-environment variable)
%DIRSIZE%
%NEWFILE%
%COMM%
%HTTP DIR%
%HOSTNAME%
%FTPDIR%
%TZ%
%SOCKETS%
%LIBPATH%
LIBPATH (environment variable)
Windir (Windows environment variable)
Windir (environment variable)
LOCALAPPDATA (Windows environment variable)
LOCALAPPDATA (environment variable)
LOCALAPPDATA
ProgramFiles (Windows environment variable)
ProgramFiles (environment variable)
ProgramFiles
ProgramFiles(x86) (Windows environment variable)
ProgramFiles(x86) (environment variable)
ProgramFiles(x86)
ProgramW6432
ProgramW6432 (environment variable)
ProgramW6432 (Windows environment variable)
CommonProgramFiles
CommonProgramFiles (Windows environment variable)
CommonProgramFiles (environment variable)
SystemDrive (Windows environment variable)
SystemDrive (environment variable)
SystemDrive
SystemRoot
SystemRoot (environment variable)
SystemRoot (Windows environment variable)
ALLUSERSPROFILE (environment variable)
ALLUSERSPROFILE
ALLUSERSPROFILE (Windows environment variable)
PROGRAMDATA (environment variable)
PROGRAMDATA
PROGRAMDATA (Windows environment variable)
USERDOMAIN (environment variable)
USERDOMAIN
USERDOMAIN (Windows environment variable)
USERPROFILE (environment variable)
USERPROFILE
USERPROFILE (Windows environment variable)
APPDATA (environment variable)
APPDATA
APPDATA (Windows environment variable)
%APPDATA%
%LOCALAPPDATA%
%ProgramFiles%
%ProgramFiles(x86)%
%ProgramW6432%
%CommonProgramFiles%
%ALLUSERSPROFILE%
%PROGRAMDATA%
%USERDOMAIN%
%USERPROFILE%
%windir%
CMDLINE (environment variable)
CONFIG (environment variable)
$LD LIBRARY PATH
%HOMEDRIVE%
%HOMEPATH%
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