O que (quem) é environment variable - definição
DYNAMIC VALUE THAT AFFECTS THE BEHAVIOR OF PROCESSES ON A COMPUTER
%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%; Setenv; Unsetenv; Environment string
environment variable
<programming, operating system> A variable that is bound in
the current environment. When evaluating an expression in
some environment, the evaluation of a variable consists of
looking up its name in the environment and substituting its
value.
Most programming languages have some concept of an environment
but in Unix shell scripts it has a specific meaning
slightly different from other contexts. In shell scripts,
environment variables are one kind of shell variable. They
differ from local variables and command line arguments in
that they are inheritted by a child process. Examples are
the PATH variable that tells the shell the file system
paths to search to find command executables and the TZ
variable which contains the local time zone. The variable
called "SHELL" specifies the type of shell being used.
These variables are used by commands or shell scripts to
discover things about the environment they are operating in.
Environment variables can be changed or created by the user
or a program.
To see a list of environment variables type "setenv" at the
csh or tcsh prompt or "set" at the sh, bash, jsh
or ksh prompt.
In other programming languages, e.g. functional programming
languages, the environment is extended with new bindings when
a function's parameters are bound to its {actual
arguments} or when new variables are declared. In a
block-structured procedural language, the environment
usually consists of a linked list of activation records.
(1999-01-26)
Environment variable
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.
shell variable
<programming, operating system> One of the variables
accessible to a Unix shell process, including {environment
variables} (e.g. $HOME), command line arguments (e.g. $1)
and local variables (e.g. $input_file). Other {operating
systems} have similar variables.
(1999-01-26)
Wikipédia
Environment variable
An environment variable is a dynamic-named value that can affect the way running processes will behave on a computer. Environment variables 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.
