Tag Archives: php

How to Test Sendmail From Command Line on Linux

What Is Sendmail?

sendmail is a very plain and simple MTA (Mail Transfer Agent), which implements the SMTP (Simple Mail Transfer Protocol) amongst others and can be used to transmit emails, typically on Linux. While there is a commercial version available which is called “Sendmail”, the sendmail we’re covering in this how-to article is the UNIX-based version of it, which comes with pretty much every Linux distribution as well as *BSD (FreeBSD, OpenBSD, and variants). Using the sendmail command might be the easiest way to send e-mails via Linux shell CLI (Command Line Interface), apart from mailx, which can be used in conjunction with sendmail to make it even easier to send and receive emails from the command line. Like the name already suggests, sendmail itself can only send emails and not store received ones in POP or IMAP mailboxes.

Where Is Sendmail And Its Configuration Files Located?

The first interesting information that we might need for testing sendmail is the path of the binary file that gets executed if we issue the command sendmail on our command line. To figure that out, we’ll use the which command as shown below:

[root@box ~]# which sendmail
/usr/sbin/sendmail

The above output means that the full path to our sendmail command’s binary file is /usr/sbin/sendmail which you should note for the steps further below.

If you want to adjust the configuration files of sendmail, you can usually find them in the directory /etc/mail/on UNIX (FreeBSD, OpenBSD) and Linux (CentOS, Fedora, Debian, Ubuntu) systems. The main configuration file of sendmail is /etc/mail/sendmail.cf, however adjusting that is not part of this tutorial. A good place for more information is the manual page of sendmail, that you can view by running the command man sendmail. Now to the interesting part of this sendmail command line tutorial.

How to Test the Sendmail Command On Linux

To quickly test if the sendmail command is working correctly to then use it for example in shell scripts, via command line or even from PHP scripts (PHP supports sendmail to send emails from PHP scripts – you can set the sendmail path in your php.ini), you can issue the below command on your UNIX or Linux system:

echo "Subject: sendmail test" | sendmail -v my@email.com

my@email.com is obviously the e-mail address you want the test email to be sent to. This sendmail command line example will send a blank email with the subject “sendmail test” to my@email.com if the test is successful. You can also send longer e-mails containing a subject, body and additional headers if you want to, but just to test if sendmail works that’s usually not required. Still, here is how you can do that:

1.) Create a file called mail.txt (or anything you like) in ~/mail.txt with vim or nano or your preferred text editor

2.) Paste the following content to it, but of course adjusting the email addresses, as those are just sendmail command examples:

To: my@email.com
Subject: sendmail test two
From: me@myserver.com
And here goes the e-mail body, test test test..

3.) At last we send the e-mail template we just created with: sendmail -vt < ~/mail.txt

That’s it – you can now test sendmail from the command line and even send full e-mails including headers from Linux/UNIX shell. Below is an example of how the simple sendmail test could look like on a live system:

sendmail test

Sendmail And Spam

One thing I’d like to add is that due to the fact that PHP and other scripts can usually access the sendmail binaries, it can also be used to send out spam and phishing mails and that’s what can happen on shared servers where accounts were compromised through an outdated CMS or weak passwords. If you want to find out which script or POSIX user is sending the spam with sendmail, you can issue the below command and pay close attention to the output:

ps faux | grep sendmail

Sendmail Conclusion

While sendmail can pose a few risks on shared or insecure systems, it is a great lightweight MTA that can be used to send e-mails from shell scripts, PHP applications or even directly the command line. It also automatically negotiates STARTTLS for encrypted transmission of the emails if the remote SMTP server supports it, which is a useful security practice.

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Welcome to the Gutenberg Editor

Of Mountains & Printing Presses

The goal of this new editor is to make adding rich content to WordPress simple and enjoyable. This whole post is composed of pieces of content—somewhat similar to LEGO bricks—that you can move around and interact with. Move your cursor around and you’ll notice the different blocks light up with outlines and arrows. Press the arrows to reposition blocks quickly, without fearing about losing things in the process of copying and pasting.

What you are reading now is a text block the most basic block of all. The text block has its own controls to be moved freely around the post…

… like this one, which is right aligned.

Headings are separate blocks as well, which helps with the outline and organization of your content.

A Picture is Worth a Thousand Words

Handling images and media with the utmost care is a primary focus of the new editor. Hopefully, you’ll find aspects of adding captions or going full-width with your pictures much easier and robust than before.

Beautiful landscape
If your theme supports it, you’ll see the “wide” button on the image toolbar. Give it a try.

Try selecting and removing or editing the caption, now you don’t have to be careful about selecting the image or other text by mistake and ruining the presentation.

The Inserter Tool

Imagine everything that WordPress can do is available to you quickly and in the same place on the interface. No need to figure out HTML tags, classes, or remember complicated shortcode syntax. That’s the spirit behind the inserter—the (+) button you’ll see around the editor—which allows you to browse all available content blocks and add them into your post. Plugins and themes are able to register their own, opening up all sort of possibilities for rich editing and publishing.

Go give it a try, you may discover things WordPress can already add into your posts that you didn’t know about. Here’s a short list of what you can currently find there:

  • Text & Headings
  • Images & Videos
  • Galleries
  • Embeds, like YouTube, Tweets, or other WordPress posts.
  • Layout blocks, like Buttons, Hero Images, Separators, etc.
  • And Lists like this one of course 🙂

Visual Editing

A huge benefit of blocks is that you can edit them in place and manipulate your content directly. Instead of having fields for editing things like the source of a quote, or the text of a button, you can directly change the content. Try editing the following quote:

The editor will endeavor to create a new page and post building experience that makes writing rich posts effortless, and has “blocks” to make it easy what today might take shortcodes, custom HTML, or “mystery meat” embed discovery.

Matt Mullenweg, 2017

The information corresponding to the source of the quote is a separate text field, similar to captions under images, so the structure of the quote is protected even if you select, modify, or remove the source. It’s always easy to add it back.

Blocks can be anything you need. For instance, you may want to add a subdued quote as part of the composition of your text, or you may prefer to display a giant stylized one. All of these options are available in the inserter.

You can change the amount of columns in your galleries by dragging a slider in the block inspector in the sidebar.

Media Rich

If you combine the new wide and full-wide alignments with galleries, you can create a very media rich layout, very quickly:

Accessibility is important — don’t forget image alt attribute

Sure, the full-wide image can be pretty big. But sometimes the image is worth it.

The above is a gallery with just two images. It’s an easier way to create visually appealing layouts, without having to deal with floats. You can also easily convert the gallery back to individual images again, by using the block switcher.

Any block can opt into these alignments. The embed block has them also, and is responsive out of the box:

You can build any block you like, static or dynamic, decorative or plain. Here’s a pullquote block:

Code is Poetry

The WordPress community

If you want to learn more about how to build additional blocks, or if you are interested in helping with the project, head over to the GitHub repository.


Thanks for testing Gutenberg!

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