today's howtos

posted by Roy Schestowitz on Feb 17, 2023

• How to Restrict SSH User Access to Certain Directory Using Chrooted Jail

  There are several reasons to restrict an SSH user session to a particular directory, especially on web servers, but the obvious one is system security. In order to lock SSH users in a certain directory, we can use chroot mechanism.

  change root (chroot) in Unix-like systems such as Linux, is a means of separating specific user operations from the rest of the Linux system; changes the apparent root directory for the currently running user process and its child (parent) process with a new root directory called a chrooted jail.

• Linux Ext4 directories have a maximum size (in entries)

  Congratulations, of a sort. You've managed to accumulate so many files in the directory that it has filled up, in a logical sense. Unfortunately, further attempts to create files will fail; in fact they are already failing, because that's how you get the error message. If you're lucky, your software is logging error messages and you're noticing them. Also, since your directory got so large, you may have an unpleasant surprise coming your way.

• My 2023 CSS Wishlist

  There are lots of CSS wishlists going around. This one is mine.

  Or at least, partly mine. A lot of what I would wish for has already been mentioned by others. I’ll start by echoing what they’ve said, then I’ll add a few wild ideas of my own.

• Lightweight data monitoring using RRDtool

  RRDtool stands for "Round Robin Database Tool", it's a set of programs and a specific file format to gather metrics. The trick with RRD files is that they have a fixed size, when you create it, you need to define how many values you want to store in it, at which frequency, for how long. This can't be changed after the file creation.