debugfs: add page (#4409)

pages/linux/debugfs.md

@@ -0,0 +1,27 @@
+# debugfs
+
+> An interactive ext2/ext3/ext4 filesystem debugger.
+
+- Open the filesystem in read only mode:
+
+`debugfs {{/dev/sdXN}}`
+
+- Open the filesystem in read write mode:
+
+`debugfs -w {{/dev/sdXN}}`
+
+- Read commands from a specified file, execute them and then exit:
+
+`debugfs -f {{path/to/cmd_file}} {{/dev/sdXN}}`
+
+- View the filesystem stats in debugfs console:
+
+`stats`
+
+- Close the filesystem:
+
+`close -a`
+
+- List all available commands:
+
+`lr`