How To Block Email Using Subject Headers In Postfix

Author: , December 7th, 2021

I needed to block email based on the Subject header. The solution is simple: Edit as root and uncomment or add:

Next, creaate or edit /etc/postfix/header_checks as root and add the following line:

Finally, run sudo postfix reload NOTE: Do NOT add the “i” after the regular expression! It is case-insensitive by […]

How To Enable Focus Follows Mouse On MacOS

Author: , December 2nd, 2021

Use AutoRaise! From the docs: “When you hover a window it will be raised to the front (with a delay of your choosing) and gets the focus.” Web page: Download:

My ~/.AutoRaise file:

How To Bounce the Dock Icon For All Incoming Email on MacOS

Author: , November 2nd, 2021

I needed a way to get the dock icon to bounce for all incoming emails and there did not seem to be any option to do so. There is actually a simple way to do it, but it is not intuitive. The key is to add a new Rule! Open and choose Mail -> […]

How To Sync AWS S3 Buckets Using RClone

Author: , September 9th, 2021

The aws s3 sync command is slow and painful! I needed a more efficient way to sync to large buckets (prod to dev). Finally settled on RClone:

During rclone config I called remote “s3” ;-}

How To Get A Reverse DNS Lookup On The Command Line

Author: , September 1st, 2021

There are three commands in Linux to easily get a reverse DNS lookup with: dig, host and nslookup. Here are examples of each: shell> dig -x +short

shell> dig -x

shell> host

shell> nslookup

How To Load /etc/rc.local At Boot Time

Author: , August 12th, 2021

My /etc/rc.local was not loading at boot time. rc.local is a symlink to /etc/rc.d/rc.local lrwxrwxrwx 1 root root 13 Jun 22 2020 rc.local -> rc.d/rc.local I had to execute the following:

How To Force Postfix To Use Only IPv4

Author: , August 12th, 2021

vi /etc/postfix/

service postfix restart

How To Copy Key Pairs To Another AWS Region Using The ssh-keygen Command

Author: , August 4th, 2021

I wanted to use the same SSH keys for multiple AWS regions. As it turns out, AWS simply stores the public key when you download the private key as a .pem file. The solution is to simply generate the public key locally from the existing .pem, then import the public key using the same name […]

How To Allow AWS IAM Users EBS Snapshot Create And Delete Access

Author: , July 29th, 2021

SUMMARY: Needed to create an AWS IAM Policy to allow a user access to create and delete EBS snapshots. This script also needed to be able to list volumes:

How To Allow IAM Users AWS CDN Read/Write Access For W3 Total Cache

Author: , July 28th, 2021

SUMMARY: Needed to create an AWS IAM Policy to allow a user access to two buckets and their associated CDN’s in WordPress W3 Total Cache