Linux for the developer

These articles discuss Linux-related topics that can help as you develop or administer your web site.

Using the shebang

The shebang is a line in a script file that specifies which program should run the script. Using the correct shebang is especially important for CGI script files. This article covers what the shebang is, and provides a table of the correct shebangs for various programming languages.

Managing the inode count

The inode count represents the total number of files and directories in an account or on a disk. This article shows you how to determine the inode count for your account using cPanel or the command line. It also provides recommendations on how to reduce the inode count.

Determining high disk usage locations

Learn how to use the ‘du’ command to determine where your account is using the most disk space. This article also provides tips and recommendations for how to reduce disk usage.

Using screen

You can use the screen program to open multiple text windows within a single SSH session. If you frequently work from the command line, particularly over an unstable internet connection, screen is a valuable addition to your toolbox. This article covers basic screen usage, as well as troubleshooting steps.

Monitoring resource usage

The top and atop commands enable you to monitor resource usage for your account in real-time. This article covers how to use these command-line programs.

Using rsync

The rsync program allows you to easily synchronize directories between two locations. For example, one common use of rsync is to create a backup. This article covers when and how to use rsync, with step-by-step instructions for the command line.

Using cURL

You can use the cURL program to transfer files to your account from the command line. The cURL program is often a good substitute for the wget program. This article provides an introduction to cURL with examples on how to use it.

Disabling e-mail notifications from cron jobs

By default, cron sends e-mail notifications when it runs a cron job. This article shows how to disable this behavior.

Using ImageMagick

ImageMagick is a powerful suite of programs that are used to manipulate image files. Learn more about these programs and how to run them here.

Changing the time zone in the Linux shell

By default, Hostvento Hosting’s servers use the US Eastern Standard Time (EST) time zone. This article shows how to configure your Linux shell account to use a different time zone.

Cron jobs reset to 15-minute intervals

This article only applies to shared, hosting, and reseller accounts. For server performance and stability reasons, cron jobs with intervals less than 15 minutes are reset to 15-minute intervals automatically.

Installing and configuring Advanced Policy Firewall

You can use Advanced Policy Firewall (APF) to help secure your VPS or dedicated server. This article covers how to install APF and how to configure APF with the basic configuration, and how to grant and deny access.

Configuring a firewall using iptables

The iptables program enables you to set up a firewall and help secure your server. Please note that this article only applies to unmanaged hosting packages. This article gives you an overview of the iptables program, how to add and insert rules, how to block an IP address, delete rules, and save rules (in Debian and Ubuntu, as well as CentOS and Fedora.)

Setting the default text editor in Linux

Learn how to set the default text editor for the Linux command-line environment.

Determining a server’s memory usage

Learn how to determine the correct amount of free and used memory on a server by using the “free” command.

Generate and verify file checksums on Linux

Learn what a checksum is, how to generate MD5 and SHA checksums for files on Linux, and how to verify file integrity in this article.

Installing the EPEL repository on CentOS

The Extra Packages for Enterprise Linux (EPEL) repository contains many additional useful packages for CentOS. Learn how to install this repository on your unmanaged server.

Running a cron job after a server reboot

You may want to run a script or application in a cron job automatically after a server reboots. This article shows you how to use the “@reboot” crontab directive to do so.

Understanding system load averages

This article discusses how to view and interpret system load averages using information from the command line.

Conntrack sessions

This article discusses what conntrack sessions are, why they are important, how to monitor them for your server, and what to do if the number of conntrack sessions is high.

Installing and configuring UFW (Uncomplicated Firewall)

This article describes how to install UFW (Uncomplicated Firewall) and set up some basic configuration rules. Note that you must have root-level access to the server to follow the procedures in this article.