sfill: add page (#5745)

pages/linux/sfill.md

@@ -0,0 +1,24 @@
+# sfill
+
+> Securely overwrite the free space and inodes of the partition where the specified directory resides.
+> More information: <https://manned.org/sfill>.
+
+- Overwrite free space and inodes of a disk with 38 writes (slow but secure):
+
+`sfill {{/path/to/mounted_disk_directory}}`
+
+- Overwrite free space and inodes of a disk with 6 writes (fast but less secure) and show status:
+
+`sfill -l -v {{/path/to/mounted_disk_directory}}`
+
+- Overwrite free space and inodes of a disk with 1 write (very fast but insecure) and show status:
+
+`sfill -ll -v {{/path/to/mounted_disk_directory}}`
+
+- Overwrite only free space of a disk:
+
+`sfill -I {{/path/to/mounted_disk_directory}}`
+
+- Overwrite only free inodes of a disk:
+
+`sfill -i {{/path/to/mounted_disk_directory}}`