nvram: add page (#6617)

pages/osx/nvram.md

@@ -0,0 +1,28 @@
+# nvram
+
+> Manipulate firmware variables.
+> More information: <https://ss64.com/osx/nvram.html>.
+
+- [p]rint all the variables stored in the NVRAM:
+
+`nvram -p`
+
+- [p]rint all the variables stored in the NVRAM using [x]ML format:
+
+`nvram -xp`
+
+- Modify the value of a firmware variable:
+
+`sudo nvram {{name}}="{{value}}"`
+
+- [d]elete a firmware variable:
+
+`sudo nvram -d {{name}}`
+
+- [c]lear all the firmware variables:
+
+`sudo nvram -c`
+
+- Set a firmware variable from a specific [x]ML [f]ile:
+
+`sudo nvram -xf {{path/to/file.xml}}`