Redirect a subdomain in Apache and keep the URL in the address bar

Apache Redirect

This tutorial shows you how to use redirect rules in the Apache web server. If you want to redirect a subdomain like sub.domain.tld into a subdirectory of the website and keep the original URL in the browser location bar, you may use the following apache directive. RewriteEngine on RewriteCond %{HTTP_HOST} ^sub.domain.tld [NC] RewriteRule ^/(.*)$ /sub/$1 ... Read more

How to convert filenames or text to lowercase on the Linux command line

Linux tolower command

There is no simple 'tolower' command on the bash, but you can convert uppercase characters to lowercase with a little shell script. The script uses the tr command internally for converting the chars. Create a shell script with the name 'tolower' that converts all text that is given as a command-line argument to lower case: ... Read more

How to speed up logins in pure-ftpd on Debian or Ubuntu Linux by disabling name resolution

PureFTPD DontResolve

If you experience problems with slow logins in pure-ftpd, this is often caused by a problem with the resolving of the client's hostname. This happens e.g. when you run an FTP server in your intranet and the hostname of the client computer does not exist in DNS. Disable PureFTPD name resolver To disable name resolving ... Read more

Get detailed information about server hardware and partitions on Ubuntu

Get Hardware info on Ubuntu

This short tutorial shows you 5 commands to get details about the system hardware of your PC, Notebook, or Server on Ubuntu and Debian. CPU details on Linux To get detailed information on the CPU, use this command: cat /proc/cpuinfo The output will look similar to this: cat /proc/cpuinfo processor       : 0 vendor_id       : AuthenticAMD ... Read more

Configure fail2ban to use route instead of iptables to block connections

Fail2ban route command

Fail2ban uses iptables by default to block incoming connections when they exceed the max.  login retries. The iptables rules used by fail2ban might conflict with other firewall rules, so it might be necessary to reconfigure fail2ban to use the route command for blocking incoming connections. Fail2ban ban using route command To reconfigure fail2ban for using ... Read more

Backup and Restore MySQL Databases on the shell

MySQL Database Backup

One way to create a backup of a MySQL database on the shell is to use the mysqldump command. Mysqldump creates a dump of the database in form of sql commands, which can be easily restored using the mysql command or PHPMyAdmin. Backup a MySQL Database mysqldump -u root -p mydatabase > /tmp/backup_mydatabase.sql This command ... Read more

How to enable verbose logging in pure-ftpd on Debian and Ubuntu

PureFTPD Verbose Log

To turn on verbose logging (e.g. to debug FTP connection or authentication problems) in pure-ftpd FTP server on Debian and Ubuntu Linux. Enable debug log in pure-ftpd Execute the following command as root user in the shell to enable verbose logging: echo 'yes' > /etc/pure-ftpd/conf/VerboseLog and then restart pure-ftpd, for init based systems: service pure-ftpd-mysql ... Read more

Linux: How to view log files on the shell

Many Linux servers are administered on the command line e.g. with an SSH connection. In the following article, I will explain several shell commands that make it easy to view log files. These commands will work on all major Linux distributions inc. CentOS, Debian, Fedora, and Ubuntu. Get the last N lines of a log ... Read more

Redirect domains without www (e.g. domain.com) to www.domain.com with apache rewrite rules

Apache www redirect rule

If all your visitors shall access your website with a URL like www.domain.com and not without www, use the following apache rewrite rule for redirecting them. RewriteEngine On RewriteCond %{HTTP_HOST} !^www RewriteRule (.*) http://www.%{HTTP_HOST}$1 [L,R] The apache rewrite rule can be added in a .htaccess file in the website root directory or if you use ... Read more

How to Backup/Clear/Restore a SpamAssassin Bayes Database

SpamAssassin Bayes Database

Sometimes you might have to work with the Spamassin Bayes Token database. This is the database that is used by the SpamAssassin Self Learning (Bayesian) Classifier to store the ham and spam tokens. This tutorial will show you how to make a backup of that database. E.g. when you want to move it to a ... Read more