Export/SET environment variables in windows through a shell script

Question

There is a script.sh file

 set FABRIC_CFG_PATH=<some path>
 set CORE_PEER_LOCALMSPID=<some id>

If I'm running this script in windows, the env variables are not getting set. Whereas if setting the env using the cmd approach, E.g., on windows cmd set FABRIC_CFG_PATH=<some path> It works fine.

So how can I set the env in windows through a shell script file?

Answer 1

Since your intent is to define current-process-only environment variables (rather than persistently defined ones, which on Windows are stored in the registry) you need to use a script file / batch file that runs in-process in order for environment variables defined therein to be seen by the script's caller.

Therefore:

• If the caller is a cmd.exe session, you must use a batch file: a plain-text file with filename extension .cmd (or, less preferably, .bat^[1]) that uses cmd.exe syntax.

• If the caller is a PowerShell session, you must use a PowerShell script: a plain-text file with filename extension .ps1 that uses PowerShell syntax.

  • Note: While you can call a .cmd file (batch file) from PowerShell too (but not directly vice versa), this will not work as intended, because of necessity it runs in a (cmd.exe) child process, whose environment variables aren't seen by the PowerShell caller.

As for .sh files: they have no predefined meaning on Windows, but may be defined by third-party applications, such as Git Bash. In the case of the latter, invoking a .sh file passes it to the POSIX-compatible Bash shell, which has its own syntax. More importantly, invoking such a file won't work as intended when called from either cmd.exe or PowerShell, because Bash must run in a child process, and child processes cannot set environment variables for their parents.

---

cmd.exe / batch-file example:

Create a file named envVars.cmd, for instance, and place the following lines in it:

@echo off
:: Note: Do NOT use `setlocal` here
set "FABRIC_CFG_PATH=C:\path\to\some directory\config"
set "CORE_PEER_LOCALMSPID=42"

Then, from your cmd.exe session / another batch file, call the file as follows to make the environment variable-definitions take effect for the current process (assuming the file is in the current directory):

.\envVars.cmd

You will then able to refer to the newly defined variables as %FABRIC_CFG_PATH% and %CORE_PEER_LOCALMSPID%.

---

PowerShell example:

Create a file named envVars.ps1, for instance, and place the following lines in it:

$env:FABRIC_CFG_PATH='C:\path\to\some directory\config'
$env:CORE_PEER_LOCALMSPID=42

Then, from a PowerShell session / another PowerShell script, call the file as follows to make the environment variable-definitions take effect for the current process (assuming the file is in the current directory):

./envVars.ps1

You will then able to refer to the newly defined variables as $env:FABRIC_CFG_PATH and $env:CORE_PEER_LOCALMSPID.

---

^{[1] See this answer.}

Answer 2

After some study on the executables/batch files in windows, I have come to the conclusion that I need to write a batch .bat file to use the set command to set the env variables as I desire.