debman: add page (#3542)

pages/linux/debman.md

@@ -0,0 +1,15 @@
+# debman
+
+> Read man pages from uninstalled packages.
+
+- Read a man page for a command that is provided by a specified package name:
+
+`debman -p {{package_name}} {{command_name}}`
+
+- Specify a package version to download:
+
+`debman -p {{package_name}}={{version}} {{command_name}}`
+
+- Read a man page in a .deb file:
+
+`debman -f {{path/to/filename.deb}} {{command_name}}`