HOWTO: force filesystem check on reboot in a Linux system

Usually, only a superficial file system check is performed automatically on boot up, and it's sufficient; but sometimes it could be handy to force a full file system check (i. e., to run the Linux fsck utility) to ensure the FS is really OK.

1. Classic init (SysVinit): just reboot the system with a special option:

   # shutdown -rF now

2. systemd init: much more interesting: at the boot time, you need to append a special kernel command line parameter (e. g., you can specify it at the GRUB command line):

   linux /boot/vmlinuz root=UUID=... ro fsck.mode=force

P. S. It should then check all the filesystems enabled for checking in /etc/fstab.

References:

1. man shutdown
2. man systemd-fsck
3. man fstab
4. man fsck

TestDisk & PhotoRec: nice tools to recover lost partitions & files

TestDisk + PhotoRec is a nice toolset to recover lost disk partitions (or at least rescue some files from corrupted filesystems) in case of storage media failures, re-partitioning errors etc.
Works for disk images too.
More to say, it's a free & open source (GPL v2+) cross-platform (Linux, *BSD, Apple Mac OS X, Oracle / Sun Solaris, MS-DOS, MS Windows) software.

Presently, in Debian-based Linux distros, TestDisk & PhotoRec have been packaged into a single testdisk package, so you can install both tools at once:

# apt-get install testdisk

Free & open source data encryption software: quick list

Here is a quick list of free & open source on-the-fly filesystem (FS) encryption software.

• Entire disk / volume / partition encryption & "virtual disk" (container file)-based software:
  • LUKS / dm-crypt [Linux (FS driver is implemented at kernel level); encrypted volumes are supported by FreeOTFE in MS Windows];
  • FreeOTFE [MS Windows];
  • DiskCryptor [MS Windows];
  • TrueCrypt [MS Windows, Mac OS X, Linux] (discontinued in 2014-05).
• File-level encryption tools:
  
  • eCryptfs [Linux (FS driver is implemented at kernel level)];
  • EncFS [Linux (FUSE-based FS); experimental MS Windows port exists: encfs4win];
  • antigift (a ccrypt wrapper) [Linux, FreeBSD, Mac OS X, MS Windows].

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Last updated: 2014-06-19