Book Image

Mastering Bash

By : Giorgio Zarrelli
Book Image

Mastering Bash

By: Giorgio Zarrelli

Overview of this book

System administration is an everyday effort that involves a lot of tedious tasks, and devious pits. Knowing your environment is the key to unleashing the most powerful solution that will make your life easy as an administrator, and show you the path to new heights. Bash is your Swiss army knife to set up your working or home environment as you want, when you want. This book will enable you to customize your system step by step, making your own real, virtual, home out of it. The journey will take you swiftly through the basis of the shell programming in Bash to more interesting and challenging tasks. You will be introduced to one of the most famous open source monitoring systems—Nagios, and write complex programs with it in any languages. You’ll see how to perform checks on your sites and applications. Moving on, you’ll discover how to write your own daemons so you can create your services and take advantage of inter-process communication to let your scripts talk to each other. So, despite these being everyday tasks, you’ll have a lot of fun on the way. By the end of the book, you will have gained advanced knowledge of Bash that will help you automate routine tasks and manage your systems.
Table of Contents (15 chapters)

Restricted sftp sessions with OpenSSH

Using OpenSSH, everything can be easily done with five configuration lines and a few commands; let's see how. We are on the remote server.

First, let's open the OpenSSH file, which is usually found in /etc/ssh/sshd_config and add these few lines:

Match group sftp-only
ChrootDirectory /opt/jails/%u/exchange
X11Forwarding no
AllowTcpForwarding no
ForceCommand internal-sftp

We should already know what these directives are, but let's recall what we wrote in Chapter 12, Remote Connections over SSH, about remote connections over ssh:

  • Match: With this directive, we can use conditional statements so that if they are satisfied the following configuration lines, we will override the ones in the main configuration block. If a keyword/configuration block appears in more than one match clause, only the first instance is taken in to account...