Return the value of the environment variable var.
For example,
getenv ("PATH") returns a string containing the value of your path.
Set the value of the environment variable var to value.
If no value is specified then the variable will be assigned the null string.
Delete the environment variable var.
Return 0 if the variable was deleted, or did not exist, and -1 if an error occurred.
Return the current home directory.
On most systems, this is equivalent to getenv ("HOME"). On Windows systems, if the environment variable HOME is not set then it is equivalent to fullfile (getenv ("HOMEDRIVE"), getenv ("HOMEPATH"))
See also: getenv.
© 1996–2018 John W. Eaton
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https://octave.org/doc/interpreter/Environment-Variables.html