bash

How to Use Gmail to Send Email with Postfix on Ubuntu

 in Bash / GNU/Linux  tagged bash / email / gmail / GNU/Linux / postfix / sasl_passwd / ubuntu by

Introduction

In today’s digital age, email has become integral to our personal and professional lives. While numerous email clients are available, Gmail remains a popular choice due to its user-friendly interface and powerful features. In this blog post, we will guide you through configuring Postfix, a famous mail transfer agent (MTA), to send emails using your Gmail account on an Ubuntu system. Let’s dive in!

Prerequisites:

Before we begin, make sure you have the following prerequisites in place:

  1. An Ubuntu system with administrative privileges.
  2. A Gmail account.
  3. A basic understanding of the Linux command line.

Step 1: Install Postfix

  1. Open the terminal on your Ubuntu system.
  2. Update the package lists by running the command:
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sudo apt update;

Install Postfix by running the command:

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sudo apt install postfix;

During the installation process, you will be prompted to configure Postfix. Select “Internet Site” and press Enter. Provide your system’s mail name when prompted.

Step 2: Configure Postfix to Use Gmail

Open the main Postfix configuration file using a text editor:

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sudo nano /etc/postfix/main.cf;

Locate the following lines and modify them as shown below:

relayhost = [smtp.gmail.com]:587
smtp_use_tls = yes
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous

Save the changes and exit the text editor.

Step 3: Configure Gmail Account Credentials

Create a file to store your Gmail account credentials:

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sudo nano /etc/postfix/sasl_passwd;

Add the following line to the file:

[smtp.gmail.com]:587 your_email@gmail.com:your_app_password

Note: Replace “your_email@gmail.com” with your actual Gmail address and “your_app_password” with the application-specific password you generated for Postfix in your Google Account settings. Save the file and exit the text editor. Secure the credentials file by running the command:

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sudo chmod 600 /etc/postfix/sasl_passwd;

Update the Postfix lookup table for the credentials file by running the command:

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sudo postmap /etc/postfix/sasl_passwd;

Step 4: Restart Postfix and Test

Restart the Postfix service to apply the changes:

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sudo systemctl restart postfix;

Test the email configuration by sending a test email using the following command:

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echo "This is a test email." | mail -s "Test Email" recipient_email@bytefreaks.net;

Note: Replace “recipient_email@example.com” with the email address where you want to send the test email.

Check the recipient’s mailbox to ensure the test email was delivered successfully.

Conclusion

By configuring Postfix to use Gmail on your Ubuntu system, you can harness the power of both platforms to send emails seamlessly. This integration allows you to leverage Gmail’s advanced features while benefiting from Postfix’s reliability and customization options. With the steps outlined in this blog post, you can easily set up the connection and streamline your email communication. Happy emailing!

Bulk convert PNG images to JPG / JPEG

 in Bash / GNU/Linux  tagged bash / Bulk / convert / GNU/Linux / imagemagick / images by
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for i in *.png ; do convert "$i" "${i%.*}.jpg" ; done

The command “for i in .png ; do convert “$i” “${i%.}.jpg” ; done” is a Bash script that converts all PNG files in the current directory to JPEG files.

Let’s break down this command:

  • “for i in *.png ;” is a loop that iterates over each PNG file in the current directory.
  • “$i” is the name of the current PNG file being processed.
  • “convert” is a command-line tool that is part of the ImageMagick software suite. It is used for image conversion, resizing, and manipulation.
  • “${i%.}.jpg” is the new filename that the PNG file will be converted to. The “${i%.}” syntax is used to remove the file extension from the original PNG file name, leaving just the base filename, which is then followed by “.jpg” to indicate that the new file should be a JPEG file.

In summary, this command converts each PNG file in the current directory to a JPEG file with the same base filename. For example, “example.png” would be converted to “example.jpg”. This command can be useful when you have a large number of PNG files that you need to convert to JPEG format quickly and easily.

How to monitor all outgoing requests/connections from your GNU/Linux machine

 in Bash / GNU/Linux  tagged bash / connections / GNU/Linux / netstat / network / server by
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netstat -nputw;

The “netstat” command is a network utility tool used to display information about active network connections, including the protocol used (TCP or UDP), the local and remote addresses and port numbers, and the current state of the connection.

The options used in this command are as follows:

  • “n” displays addresses and port numbers in numerical form rather than converting them to hostnames and service names.
  • “p” shows the process ID (PID) and program name using the connection.
  • “u” displays UDP connections.
  • “t” displays TCP connections.
  • “w” displays raw sockets.
  • “;” separates the command from other commands that may follow.

Therefore, the command netstat -nputw; will display all current network connections on the machine, including the corresponding processes and raw socket connections, in a numerical format without resolving hostnames and service names.

How to empty the gnome tracker3 cache?

 in Bash / GNU/Linux  tagged bash / clear cache / daemon / free space / gnome / GNU/Linux / tracker3 / ubuntu by

To empty the cache of gnome tracker3, you can follow the steps below:

Open a terminal window by pressing Ctrl + Alt + T.

Type the following command to stop the tracker daemon:

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tracker3 daemon -t;

Type the following command to clear the tracker database:

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tracker reset --filesystem;

This command will remove all indexed data from the tracker and clear its cache. (Remove filesystem indexer database)

Restart the tracker daemon by typing the following command:

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tracker daemon -s ;

This will start the tracker daemon again, and it will begin to rebuild its database and cache.

After following these steps, the cache of gnome tracker3 will be emptied.

Execution example:

$ tracker3 daemon -t
Found 1 PID…
  Killed process 13705 — “tracker-miner-fs-3”
$ tracker3 reset --filesystem
Found 1 PID…
  Killed process 13705 — “tracker-miner-fs-3”
$ tracker3 daemon -s
Starting miners…
  ✓ File System