Tag: Command-line

Servers can automatically perform tasks that you would otherwise have to perform yourself, such as running scripts. On Linux servers, the cron utility is the preferred way to automate the running of scripts.

There are two main ways to get cron to run a script. The first is to place a script into one of the following directories:

Servers do a fantastic job of writing down in log files what is happening right that moment. While going back and reading logs later to determine what happened in the past is helpful, it is also useful to watch logs in real time. Linux provides a command line tool that lets us do just that: tail.

One component of Liquid Web’s Server Secure service is an Apache module called Mod Security (often shortened to just “modsec”). Modsec monitors all incoming HTTP requests for malicious behavior and does not complete requests that meet certain criteria. These criteria are spelled out in what are called “rules” or “rulesets”.

Many articles in this knowledge base advise editing configuration files. We usually recommend using your preferred text editor. At Liquid Web, we prefer vim. Vim, or its older sibling vi, are installed by default on nearly every dedicated server that we come across. If you do not yet have a preferred text editor, read on to see if vim might work for you.

One of the best tools you can use when tracking down e-mail problems is mail logs. On Liquid Web’s cPanel servers, we have turned on all of exim’s logging capabilities. Full logging means that there is a lot going on, and trying to decipher the logs can be cryptic at first. Let’s take a look at how they are composed.

Note: this article assumes that you have found the mail transaction you are looking for using exigrep.

One of the most common tasks that a website owner will do is upload one or more files to their site. While it is a simple task, there are many ways to go about accomplishing it, each with their own quirks and best practices.

Linux has a robust permissions system. This is a very good thing, as it enables a clear separation of roles among users, especially between the root user and your average user. Sometimes, though, you might want your average user to have some or all of root's privileges. In Linux, this is accomplished with sudo.

Due to the nature of the Internet, services for one domain do not need to be on one server. The website and email for a domain do not need to be on the same physical server. DNS is used to direct the traffic to the correct place, but DNS alone will not get all the bits to where they are supposed to be. Exim, cPanel’s SMTP service needs a little help beyond DNS to know how to handle mail that is generated locally. This is where /etc/localdomains and /etc/remotedomains come into play.

While editing files on a machine running some form of Windows and uploading them to a Linux server is convenient, it can cause unforeseen complications. Windows-based text editors put special characters at the end of lines to denote a line return or newline. Normally harmless, some applications on a Linux server cannot understand these characters and can cause the service to not respond correctly. There is a simple way to correct this problem: dos2unix.

The time on your dedicated server might not be something you think about every day, but it is vitally important to keeping every piece of your server running in sync. Since it is so crucial, a lot of effort has been made by Linux developers to make it run smoothly without much effort. However, there are a few things you are going to be able to want to do with time on your server.