Jan 192014

Article by Rahul Panwar first posted on http://linuxexplore.com/

A chroot on Unix operating systems is an operation that changes the apparent root directory for the current running process and its children. A program that is run in such a modified environment cannot name (and therefore normally not access) files outside the designated directory tree. The term “chroot” may refer to the chroot(2) system call or the chroot(8) wrapper program. The modified environment is called a “chroot jail”. From Wikipedia.

Why it is required? If you want to set up your Linux box as a web hosting server for its users, you may need to give SFTP access. But they can get access to whole system Linux tree, just for reading but still very unsecure. So it is mandatory to lock them in their home directory.

There are many other applications, it’s just a common example, so lets start its configuration.

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Apr 292011

sadOr perhaps i should call this “Do you remember i was upgrading to Ubuntu 11.04 ?”.

Well something is gone bad and when i rebooted to start my new Xubuntu 11.04 i got:

error: cannot read the Linux header.
error: you need to load the kernel first.

  Failed to boot both default and fallback entries.

Press any key to continue...

During the upgrade, Ubuntu has removed all old Kernel but one, and so..i find myself without a way to boot my machine.

Fortunately I did a lot of experience with Gentoo in the past, that on this occasion was very useful to recover the system.
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