 }
 { $errors "Windows CE has no concept of environment variables, so this word throws an error there." } ;
 
-{ os-env os-envs set-os-envs } related-words
+HELP: set-os-env ( value key -- )
+{ $values { "value" string } { "key" string } }
+{ $description "Set an environment variable." }
+{ $notes
+    "Names and values of environment variables are operating system-specific."
+}
+{ $errors "Windows CE has no concept of environment variables, so this word throws an error there." } ;
+
+HELP: unset-os-env ( key -- )
+{ $values { "key" string } }
+{ $description "Unset an environment variable." }
+{ $notes
+    "Names and values of environment variables are operating system-specific."
+}
+{ $errors "Windows CE has no concept of environment variables, so this word throws an error there." } ;
+
+{ os-env os-envs set-os-env unset-os-env set-os-envs } related-words
 
 HELP: image
 { $values { "path" "a pathname string" } }

"Processor families:"
{ $subsection x86 } ;

ARTICLE: "os" "Operating System Detection"
"Operating system detection:"
{ $subsection os }
"Supported operating systems:"

ARTICLE: "system" "System interface"
{ $subsection "cpu" }
{ $subsection "os" }
{ $subsection "environment-variables" }
"Getting the path to the Factor VM and image:"
{ $subsection vm }
{ $subsection image }
