Setting Environment Variables
| Author: KiCHiK (talk, contrib) |
Setting Environmental Variables Temporarily
If you want to set an environment variable only for the installer process and its sub-processes use:
System::Call 'Kernel32::SetEnvironmentVariable(t, t)i ("name", "value").r0' StrCmp $0 0 error ExecWait ProgThatReadsEnv.exe Goto done error: MessageBox MB_OK "Can't set environment variable" done:
To work around the NSIS_MAX_STRLEN limit when updating %Path% you can try this function.
| Author: turnec2 (talk, contrib) |
Setting Environmental Variables Permanently
Exisiting Variables
The WriteEnvStr and un.DeleteEnvStr functions in this page have been obsoleted by EnvVarUpdate for path settings and other variables for path lists. For simple one-value environment variables however, the following does apply. The un.DeleteEnvStr function can corrupt the contents of the PATH variable if the path being removed happens to be a subset of another path. For example, if PATH contains "C:\Windows\system32\wbem" and you remove "C:\Windows\system32" the result is "\wbem". WriteEnvStr does not prevent the duplication of entries if the user runs the installer multiple times (and the installer code does not otherwise check for duplicates). However, these routines are retained for Windows 9x and ME in the next section since EnvVarUpdate does not support the update of variables in the autoexec.bat file.
See Environmental_Variables:_append,_prepend,_and_remove_entries for more information.
Your own variable
If you're setting / deleting your own environment variable MYVAR, rather than adjusting an existing one such as the PATH environment variable:
; include for some of the windows messages defines
!include "winmessages.nsh"
; HKLM (all users) vs HKCU (current user) defines
!define env_hklm 'HKLM "SYSTEM\CurrentControlSet\Control\Session Manager\Environment"'
!define env_hkcu 'HKCU "Environment"'
; set variable for local machine
WriteRegExpandStr ${env_hklm} MYVAR MYVAL
; and current user
WriteRegExpandStr ${env_hkcu} MYVAR MYVAL
; make sure windows knows about the change
SendMessage ${HWND_BROADCAST} ${WM_WININICHANGE} 0 "STR:Environment" /TIMEOUT=5000
And for your uninstaller
; delete variable
DeleteRegValue ${env_hklm} MYVAR
DeleteRegValue ${env_hkcu} MYVAR
; make sure windows knows about the change
SendMessage ${HWND_BROADCAST} ${WM_WININICHANGE} 0 "STR:Environment" /TIMEOUT=5000
Function Code
| Author: KiCHiK (talk, contrib) |
Functions for Windows 95, 98, and ME
If you want to set an environment variable that will stick for every other process and after reboots too you should use the functions below. To use them either save them as a .NSH file and include them in your script, or just copy paste them in your script. If you choose to save them as a .NSH file use:
!include WriteEnvStr.nsh # or the name you chose # ... Section "Add Env Var" Push MyEnvVar Push MyEnvVarValue Call WriteEnvStr SectionEnd # ... Section uninstall # remove the variable Push MyEnvVar Call un.DeleteEnvStr SectionEnd
If you want the environment variable to be available to all of the users using the computer define ALL_USERS before you include WriteEnvStr.nsh (or before the part of the script holding these functions if you didn't save it as a .NSH file). For example:
!define ALL_USERS !include WriteEnvStr.nsh # or the name you chose
Function Code
Note: under Windows 9x a reboot is required for changes to take effect. The reboot flag will be set by these functions if a reboot is required. Warning: this script will only work on NSIS 2.0b2 and above!
!ifndef _WriteEnvStr_nsh !define _WriteEnvStr_nsh !include WinMessages.nsh !ifndef WriteEnvStr_RegKey !ifdef ALL_USERS !define WriteEnvStr_RegKey \ 'HKLM "SYSTEM\CurrentControlSet\Control\Session Manager\Environment"' !else !define WriteEnvStr_RegKey 'HKCU "Environment"' !endif !endif # # WriteEnvStr - Writes an environment variable # Note: Win9x systems requires reboot # # Example: # Push "HOMEDIR" # name # Push "C:\New Home Dir\" # value # Call WriteEnvStr # Function WriteEnvStr Exch $1 ; $1 has environment variable value Exch Exch $0 ; $0 has environment variable name Push $2 Call IsNT Pop $2 StrCmp $2 1 WriteEnvStr_NT ; Not on NT StrCpy $2 $WINDIR 2 ; Copy drive of windows (c:) FileOpen $2 "$2\autoexec.bat" a FileSeek $2 0 END FileWrite $2 "$\r$\nSET $0=$1$\r$\n" FileClose $2 SetRebootFlag true Goto WriteEnvStr_done WriteEnvStr_NT: WriteRegExpandStr ${WriteEnvStr_RegKey} $0 $1 SendMessage ${HWND_BROADCAST} ${WM_WININICHANGE} \ 0 "STR:Environment" /TIMEOUT=5000 WriteEnvStr_done: Pop $2 Pop $0 Pop $1 FunctionEnd # # un.DeleteEnvStr - Removes an environment variable # Note: Win9x systems requires reboot # # Example: # Push "HOMEDIR" # name # Call un.DeleteEnvStr # Function un.DeleteEnvStr Exch $0 ; $0 now has the name of the variable Push $1 Push $2 Push $3 Push $4 Push $5 Call un.IsNT Pop $1 StrCmp $1 1 DeleteEnvStr_NT ; Not on NT StrCpy $1 $WINDIR 2 FileOpen $1 "$1\autoexec.bat" r GetTempFileName $4 FileOpen $2 $4 w StrCpy $0 "SET $0=" SetRebootFlag true DeleteEnvStr_dosLoop: FileRead $1 $3 StrLen $5 $0 StrCpy $5 $3 $5 StrCmp $5 $0 DeleteEnvStr_dosLoop StrCmp $5 "" DeleteEnvStr_dosLoopEnd FileWrite $2 $3 Goto DeleteEnvStr_dosLoop DeleteEnvStr_dosLoopEnd: FileClose $2 FileClose $1 StrCpy $1 $WINDIR 2 Delete "$1\autoexec.bat" CopyFiles /SILENT $4 "$1\autoexec.bat" Delete $4 Goto DeleteEnvStr_done DeleteEnvStr_NT: DeleteRegValue ${WriteEnvStr_RegKey} $0 SendMessage ${HWND_BROADCAST} ${WM_WININICHANGE} \ 0 "STR:Environment" /TIMEOUT=5000 DeleteEnvStr_done: Pop $5 Pop $4 Pop $3 Pop $2 Pop $1 Pop $0 FunctionEnd !ifndef IsNT_KiCHiK !define IsNT_KiCHiK # # [un.]IsNT - Pushes 1 if running on NT, 0 if not # # Example: # Call IsNT # Pop $0 # StrCmp $0 1 +3 # MessageBox MB_OK "Not running on NT!" # Goto +2 # MessageBox MB_OK "Running on NT!" # !macro IsNT UN Function ${UN}IsNT Push $0 ReadRegStr $0 HKLM \ "SOFTWARE\Microsoft\Windows NT\CurrentVersion" CurrentVersion StrCmp $0 "" 0 IsNT_yes ; we are not NT. Pop $0 Push 0 Return IsNT_yes: ; NT!!! Pop $0 Push 1 FunctionEnd !macroend !insertmacro IsNT "" !insertmacro IsNT "un." !endif ; IsNT_KiCHiK !endif ; _WriteEnvStr_nsh
