Windows 环境变量

Windows System Environment VariablesThese system environment variables are automatically created by Windows upon boot-up in Windows Registry key HKEY_LOCAL_MACHINE\ SYSTEM\ CurrentControlSet\ Control\ Session Manager\ EnvironmentVariable Sample Typical Value%SystemDrive% C:%SystemRoot% C:\WINDOWSC:\WINNT%WinDir% C:\WINDOWSC:\WINNT%SystemDirectory% C:\WINDOWS\System32C:\WINNT\System32%ComSpec% C:\WINDOWS\system32\cmd.exeThe path including the command interpreter program.%programfiles% C:\WINDOWS\Program Files%Temp% C:\Users\W\AppData\Local\Temp on Windows Vista & 2008C:\DOCUME~1\Usr\LOCALS~1\Temp (compressed form of)C:\Documents and Settings\Usr\Local Settings\Temp%Tmp%%HOMEDRIVE% C: The drive letter associated with the user's home directory%HOMEPATH% The path to the user's home directory as defined in UMD/AD (excluding drive):\Users\<USERNAME> on Windows Vista & 2008\Documents and Settings\Guest on Windows XP%OS% Windows_NT (even on Windows Vista & XP machinesThe operating system the user is running%USERDOMAIN% The name of the domain that contains the user's account. On a stand-alone machine, the same as the machine name.%USERNAME% The user's name%USERPROFILE% C:\Users\<USERNAME> — The user's root folder%USERPROFILE%\Desktop The user's desktop folderIf you have the permissions, invoke, then open my DOS batch file 1envvars.bat which lists the values of these variables on your computerWindows resolves commands typed in the start/run box first from files in %SYSTEMDRIVE%, then files in %SYSTEMROOT%. This is regardless of the systemdrive (such as E:) being later in the path. This means that a rogue file can be invoked instead of a good file (such as cmd.exe) if it's in the %SYSTEMDRIVE%.Below are dynamic environment variables:Variable Sample Typical Value%CD% The current directory.%DATE% Current date in the format set by the Date command%TIME% Current time in the format set by the Time command%ERRORLEVEL% A number defining exit status of a previous command or called executable.%RANDOM% A random number between 0 and 32767.You can quickly reach the folder specified within an environment variable by typing that variable on the Address bar of Windows Explorer:User Environment Variables Added by ApplicationsUser environment variables are stored in Windows Registry HKEY_CURRENT_USER\EnvironmentWithin a command batch file, to list Oracle Environment Variablesecho ORACLE_SID = %ORACLE_SID%echo ORACLE_HOME = %ORACLE_HOME%echo ORA_NLS = %ORA_NLS%echo.echo PATH = %PATH%echo.echo Machine Name to messenger service:net nameNovell adds these environment variables during installation.Variable%USER%%NWUSERNAME%%NWLANGUAGE%Creating Variables on WindowsEnvironment Variables can be created and changed using several mechanisms:By Windows automatically upon boot-up.By application programs using Windows OS API functions. This is commonly done by application installation programs.Manually using GUI in System Properties, Advanced tab, Environment Variable button. Get to this one of two ways:a). right-click My Computer icon, select Properties,b). click Start > Control Panel > System iconClick the Advanced tab, New for a new variable or Edit for an existing variable listed.System variables are available to all users.Manually using commands typed into the DOS Command Window obtained one of two ways:a). click Programs | Accessories | Command Promptb). click Run..., type cmd and press Enter.To see all variables, type:SETWindows uses a tilde ~ character to substitute for parts of file and folder names longer than 8 characters.To use the SET command to define a single variable:SET CLASSPATH=.;path1The dot specifies the current directory. The semicolon separates two folders. If the variable was already established, this will replace its value.To add a value in front of the existing value, refer to itself:SET CLASSPATH=path1;%CLASSPATH%Variables created with SET are only valid for the current session and will not be available after the command window is closed or the computer reboots.By commands executed from within an AUTOEXEC.BAT file or host script filerun this sample logon.bat file. (Click Open when prompted. Your firewall may -- rightfully -- block this.)MS PATHThe operating system looks for executables down the list of folders listed in the PATH User variable. The operating system uses the first occurance it finds. So watch out for multiple versions of the same program. For example, the Oracle install automatically adds:Program Files\Oracle\JRE\1.1.7\Bin;To enable command line invocation of compiler program csc.exe of the Microsoft .NET Framework, add this to the end of your PATH environment variable.ClickRight-click on "My Computer" to select Properties.Click the "Advanced" tab.Click the "Environment Variable" button.Scroll down the "System variables" list to the "Path" variable.Double click on "Path"Press the "End" keyType (beginning with a semicolon separator) ;%systemroot%\Framework\v1.1.4322Click "OK"Click "OK" to close the System Properties window.Verify the change:ClickClick Run... for a Run window.Type "cmd" in the Open: field.Click "OK"Type a command such as "csc"You are unsuccessful if you get back a response such as'csc' is not recognized as an internal or external command,operable program or batch file.To spare its users, most commercial applications provide an installer which does this automatically. For example, Microsoft .NET Framework SDK has a vcvars32.bat file to update paths on Windows 9x machines.Avoid spaces in path names (for backward compatibility and to avoid trouble) by using the 8 character equivalents.For example, to reachC:\Program Files\Mercury Interactive\Mercury LoadRunner\binspecifyC:\PROGRA~1\MERCUR~1\MERCUR~1\binThe sequence in my PATH:C:\PROGRA~1\Java\jdk1.5.0_02\bin;C:\PROGRA~1\MERCUR~1\MERCUR~1\classes;%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;%systemroot%\\Framework\v1.1.4322;C:\Program Files\Microsoft SQL Server\80\Tools\Binn\;c:\Program Files\Microsoft Visual Studio .NET 2003\SDK\v1.1\Bin;c:\program files\microsoft platform sdk for windows xp sp2\includeUNIX Environment VariablesIn UNIX/Linux systems, to list environment variables:envIn UNIX/Linux systems, add a dollar sign ($) in front of each variable name in all caps:echo $LOGNAME user name used for loginecho $USER user name (sudo)echo $UID user name Solarisecho $SHELL directory containing OS shell executablesecho $PATH directories containing executables, searched to find applications when no absolutepath is specified on the command line.echo $LD_LIBRARY_PATH path to system and user librariesecho $MANPATH directory containing manualsecho $HOME directory of user's home directoryecho $TZ time zone, such as "US/Mountain"In UNIX systems, the colon (:). In Windows systems, the semi-colon (;) is used. So to list each path in a separate line:echo $PATH | tr ':' '\n'Solaris systems have additional ones, including:echo $BASH path to the shell on the file system.echo $HOSTNAME name of the current system.echo $PPID parent process IDecho $WINDOWMANAGER name of the X11 window managerecho $COLUMNS The column width for the terminalecho $DISPLAY The display variable used for X11 graphics.Creating Variables on LinuxTo update an environment variable that lives until the next reboot:#export PATH=�/usr/local/XXX/bin:$PATH�#echo $PATHNotice that colons are used to separate path items.To create an environment variable that lives forever, update your .bash_profile file:XXXPATH=�/usr/local/XXX/bin�export XXXPATHFor a list of environment settings (arguments) for a process with PID 23141 (on Solaris):pargs -ae 23141Java Environment VariablesJDK versions 1.2 and 1.3 require variables Xrunmic_supp and Xbootclasspath %mic_class%The Java interpreter searches the PATH for a class by name and loads the first one it finds. So specify your own library and the most recent library first (especially if you use the same name as a class in a standard library).Also, for best performance, place the most-often used libraries at the front of the path. This applies to LIBPATH and LD_LIBRARY_PATH variables for most often used JNI libraries.Java 1.4 Documentation on Classpath notes that the preferred method for command-line tools such as java, javac, or javadoc is to NOT use environment variables but instead specify -classpath as part of the command invoking a Java program.The System environment variable CLASSPATH must be in upper case (not “classpath”). CLASSPATH is used to specify the full path and file name of every jar file used by java programs. Thus CLASSPATH could be quite long.C:\jdk1.3.1_01\src.jar;C:\jdk1.3.1_01\lib\dt.jar;C:\jdk1.3.1_01\lib\tools.jar;C:\jdk1.3.1_01\jre\lib\il8n.jar;C:\jdk1.3.1_01\jre\lib\jaws.jar;C:\jdk1.3.1_01\jre\lib\rt.jar;C:\jdk1.3.1_01\jre\demo\sound\JavaSound.jar;C:\jdk1.3.1_01\demo\jfc\SwingSet2\SwingSet2.jar;C:\jdk1.3.1_01\demo\jfc\SwingApplet\SwingApplet.jar;Sun's JDK adds:C:\jdk1.3.1_01\;C:\jdk1.3.1_01\Bin;C:\jdk1.3.1_01\Lib;A common mistake with CLASSPATH is to specify only folder paths and leave out jar file names. Semicolons should separate each jar file specification.On client machines, Microsoft's VM CLASSPATH is, by default:%windows%\Java\Classes\Classes.zip;This string is stored in environment variable CLASSPATH or Windows registry keyHKLM\Software\Microsoft\Java VM\ClasspathWindows 95/98 computers should limit CLASSPATH to less than 400 characters.Dick Baldwin notes in his tutorial that if you want the CLASSPATH to point to class files that belong to a package, you should specify a path name that includes the path to the directory one level above the directory having the name of your package.For example, suppose you want the Java interpreter to be able to find classes in the package mypackage. If the path to the mypackage directory is C:\java\MyClasses\mypackage, you would set the CLASSPATH variable as follows:set CLASSPATH=C:\java\MyClassesThe purpose of the package directive is to identify a particular class (or group of classes contained in a single source file (compilation unit)) as belonging to a specific package.NOTE: Training connection also offers some great tutorials on Java programs, Dreamweaver training, and Flex software.In Linux: pCLASSPATH=/usr/local/java/jre/binMy CLASSPATH:C:\PROGRA~1\MERCUR~1\MERCUR~1\classes;C:\PROGRA~1\MERCUR~1\MERCUR~1\classes\srv;C:\PROGRA~1\Java\jdk1.5.0_02\lib\rt.jarAmazon EC2 File PathsAmazon EC2 command script users add these environment variables. For example, if EC2 files are located in folder C:\EC2:Variable SampleEC2_HOME C:\EC2 where files are locatedEC2_PRIVATE_KEY C:\EC2\pk.pem full path to fileEC2_CERT C:\EC2\509cert.pem full path to fileWindows Network SharesChanges to variables disappear after reboot.So change the variables in a shell script or Windows network share. This mapdir.bat is an example of allocating the X: drive....This assumes that the loopback IP address has not been changed in the hosts file.。