When I tried to send the email however, I received an error message. It stated: Error. File.exe is an executable file. For security reasons, Google Mail does not allow you to send this type of file.

A click on OK displayed the compose message screen again, with the file still being attached to the email.

What I needed was a workaround. Sure, I could for instance upload the executable file to a file hosting website like Mediafire, and copy and paste the share file url in the email instead. That’s a possibility and not a bad one.

Then again, I prefer a more straightforward approach. I first tried zipping the file to see if that was enough to bypass the file filter on Gmail. It was not. The very same message was displayed and the email failed to send.

Next thing I tried was to zip the executable file and apply a password to the file to see if that would bypass the executable file filter which it did not as well. Both options did not yield the desired result. Gmail was still blocking the email from being send. I did some experiments with different encryption formats, and found out that 7-zip files that contain executable files can be send, while more common extensions like zip or gz are blocked.

Lastly I decided to change the file extension of the executable, from exe to txt. And lo and behold, the email went through the filters. Changing the file extension of the attachment can be problematic in itself, especially so if you are not the recipient of the email. You need to provide instructions, preferably in the message, that the file extension needs to be changed before the file can be run on the target computer.

So, if you want to send an executable as an attachment from your Gmail account, you either need to rename the file extension to bypass the filter, upload the file elsewhere and link to it in the mail body, or use a compression format like 7z. The latter being the most comfortable option if the recipient uses a tool that supports the unpacking of those files.

Is there an option that I have overlooked? Let me know in the comments.

As a Linux user you can add directories to your $PATH. This is helpful when you don’t want to add a command to a directory in your $PATH but you want that command to be globally executable. Doing this is actually quite easy.

What is currently in your $PATH?

NOTE: This article applies only when you are using the Bash shell. To find out what directories are included in your current $PATH issue the command:

echo $PATH

You should see something like:

/usr/lib/qt-3.3/bin:/usr/kerberos/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin:/home/jlwallen/bin

Notice the /opt directory is missing. Often the /opt directory is a great place to “install” other applications for global use. But if this directory is not in your $PATH, you will always have to use the explicit path to call a command. With that in mind let’s add /opt.

.bash_profile

In order to add a directory you have to edit a file in your ~/ (home) directory. The .bash_profile file determines user specific environment and start up programs. This file also  checks for a .bashrc file for aliases and functions, but that has nothing to do with your $PATH.

There is one particular line you need to examine in your .bash_profile:

PATH=$PATH:$HOME/bin

This is the line that determines anything extra in your $PATH. As you can see, in the example above, the extra directory added to the users’ $PATH is the ~/bin directory. Of course in most distributions this isn’t used (or even created during installation). Why ~/bin is still included I do not know. In order to add another directory to your $PATH in this line you would seperate the directories with a “:”. To add the /opt directory that line would now look like:

PATH=$PATH:$HOME/bin:/opt

As you can see the /opt directory has been added proceeding a “:”. Complete this addition and save the file. You’re not done yet.

If you issue the command echo $PATH you will still not see /opt in the users’ $PATH. Why? You have to log out and log back in before this change will take effect. So log out, log back in, and issue the command again. Issuing the command echo $PATH will not issue:

/usr/lib/qt-3.3/bin:/usr/kerberos/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin:/home/jlwallen/bin:/opt

Any command found in the /opt directory is now global.

Final thoughts

The $PATH is a very powerful tool to take advantage of in Linux. By using it you can install applications in directories outside of the norm and still make them global. I often install applications in the /opt directory or will create a /data directory for a more temporary application installation.