Update and reorganize documentation

- Convert "Common Tasks" to "How-to Guides"
  (QubesOS/qubes-issues#6694)
- Make title capitalization consistent across docs
- Fix leftover h1 headings
- Reorganize various pages and topics
- Update permalinks to better match titles
- Create redirects for changed permalinks
- Miscellaneous cleanup

QubesOS/qubes-issues#6701

user/how-to-guides/backup-emergency-restore-v2.md

@@ -0,0 +1,126 @@
+---
+lang: en
+layout: doc
+permalink: /doc/backup-emergency-restore-v2/
+redirect_from:
+- /en/doc/backup-emergency-restore-v2/
+- /doc/BackupEmergencyRestoreV2/
+ref: 207
+title: Emergency Backup Recovery (v2)
+---
+
+
+This page describes how to perform emergency restore of backup created on Qubes
+R2 Beta3 or earlier (which uses backup format 2).
+
+The Qubes backup system has been designed with emergency disaster recovery in
+mind. No special Qubes-specific tools are required to access data backed up by
+Qubes. In the event a Qubes system is unavailable, you can access your data on
+any GNU/Linux system with the following procedure.
+
+**Note:** In the following example, the backup file is assumed to be both
+encrypted and compressed.
+
+1. Untar the main backup file.
+
+    ~~~
+    [user@restore ~]$ tar -i -xvf qubes-backup-2013-12-26-123456
+    backup-header
+    backup-header.hmac
+    qubes.xml.000
+    qubes.xml.000.hmac
+    vm1/private.img.000
+    vm1/private.img.000.hmac
+    vm1/icon.png.000
+    vm1/icon.png.000.hmac
+    vm1/firewall.xml.000
+    vm1/firewall.xml.000.hmac
+    vm1/whitelisted-appmenus.list.000
+    vm1/whitelisted-appmenus.list.000.hmac
+    dom0-home/dom0user.000
+    dom0-home/dom0user.000.hmac
+    ~~~
+
+2. Verify the integrity of the `private.img` file which houses your data.
+
+    ~~~
+    [user@restore ~]$ cd vm1/
+    [user@restore vm1]$ openssl dgst -sha512 -hmac "your_passphrase" private.img.000
+    HMAC-SHA512(private.img.000)= cf83e1357eefb8bdf1542850d66d8007d620e4050b5715dc83f4a921d36ce9ce47d0d13c5d85f2b0ff8318d2877eec2f63b931bd47417a81a538327af927da3e
+    [user@restore vm1]$ cat private.img.000.hmac
+    (stdin)= cf83e1357eefb8bdf1542850d66d8007d620e4050b5715dc83f4a921d36ce9ce47d0d13c5d85f2b0ff8318d2877eec2f63b931bd47417a81a538327af927da3e
+    ~~~
+
+  **Note:** The hash values should match. If they do not match, then the backup
+  file may have been tampered with, or there may have been a storage error.
+
+  **Note:** If your backup was hashed with a message digest algorithm other
+  than `sha512`, you must substitute the correct message digest command. A
+  complete list of supported message digest algorithms can be found with
+  `openssl list-message-digest-algorithms`.
+
+3. Decrypt the `private.img` file.
+
+    ~~~
+    [user@restore vm1]$ openssl enc -d -pass pass:your_passphrase -aes-256-cbc -in private.img.000 -out private.img.dec.000
+    ~~~
+
+  **Note:** For multi-part files, a loop can be used:
+
+  ~~~
+  find -name 'private.img.*' | sort -V | while read f; do
+    openssl enc -d -pass pass:your_passphrase -aes-256-cbc -in $f -out
+  ${f/.img/.img.dec}
+  done
+  ~~~
+
+  **Note:** If your backup was encrypted with a cipher algorithm other than
+  `aes-256-cbc`, you must substitute the correct cipher command. A complete
+  list of supported cipher algorithms can be found with `openssl
+  list-cipher-algorithms`.
+
+4. Decompress the decrypted `private.img` file.
+
+    ~~~
+    [user@restore vm1]$ zforce private.img.dec.*
+    [user@restore vm1]$ gunzip private.img.dec.000.gz
+    ~~~
+
+  **Note:** If your backup was compressed with a program other than `gzip`, you
+  must substitute the correct compression program.
+
+5. Untar the decrypted and decompressed `private.img` file.
+
+    ~~~
+    [user@restore vm1]$ tar -M -xvf private.img.dec.000
+    vm1/private.img
+    ~~~
+
+    **Note:** For multi-part files, a script is required:
+
+    1. Create a `new-volume-script`:
+
+        ~~~
+        #!/bin/sh
+        name=`expr $TAR_ARCHIVE : '\(.*\)\..*'`
+        suffix=`printf %03d $[ $TAR_VOLUME - 1 ]`
+        echo $name.$suffix >&$TAR_FD
+        ~~~
+
+    2. `chmod +x new-volume-script`.
+    3. `tar --new-volume-script=./new-volume-script -xvf private.img.dec.000`.
+        (The `--new-volume-script` option enables multi-volume untaring.)
+
+6. Mount the private.img file and access your data.
+
+    ~~~
+    [user@restore vm1]$ sudo mkdir /mnt/img
+    [user@restore vm1]$ sudo mount -o loop vm1/private.img /mnt/img/
+    [user@restore vm1]$ cat /mnt/img/home/user/your_data.txt
+    This data has been successfully recovered!
+    ~~~
+
+  **Note:** You may wish to store a plain text copy of these instructions with
+  your Qubes backups in the event that you fail to recall the above procedure
+  while this web page is inaccessible. You may obtain a plaintext version of
+  this file in Git repository housing all the documentation on [Github](https://github.com/QubesOS/qubes-doc.git)