Editing Environment variable (section)

=== DOS, OS/2 and Windows ===
In DOS, OS/2 and Windows command-line interpreters such as <code>COMMAND.COM</code> and <code>CMD.EXE</code>, an environment variable is retrieved by placing a <code>%</code> sign before and after it.

In DOS, OS/2 and Windows command-line interpreters as well as their [[API]], upper or lower case is not distinguished for environment variable names.

The environment variable named <code>HOMEDRIVE</code> contains the drive letter (plus its trailing <code>:</code> colon) of the user's home directory, whilst <code>HOMEPATH</code> contains the full path of the user's home directory within that drive.

So to see the home drive and path, the user may type this:

<syntaxhighlight lang="batch">
ECHO %HOMEDRIVE%%HOMEPATH%
</syntaxhighlight>

The command '''<code>SET</code>''' (with no arguments) displays all environment variables and their values. In [[Windows NT]] and later <code>set</code> can also be used to print all variables whose name begins with a given prefix by giving the prefix as the sole argument to the command.

In [[Windows PowerShell]], the user may type any of the following:

<syntaxhighlight lang="powershell">
echo $env:homedrive$env:homepath
Write-Output $env:homedrive$env:homepath
"$env:homedrive$env:homepath"
</syntaxhighlight>

In PowerShell, upper or lower case is not distinguished for environment variable names.

The following command displays all environment variables and their values:

<syntaxhighlight lang="powershell">
Get-ChildItem env:
</syntaxhighlight>