Keep your Mac awake (disable lid and idle sleep) (how to)

A lot of people were using a convenient little application called InsomniaX to disable temporarily the sleep feature on MacOS that is activated due to inactivity after a few minutes or when you close your laptop's lid (screen). 

However, a security vulnerability was identified in the software and after that point in time it is considered a legacy software as it is no longer actively being developed. 

There are alternatives depending on what you want to do. The easiest way to keep the mac from going to sleep is to use a terminal window with the built-in command: caffeinate

However, this does not help when you change focus from that particular terminal window or need to temporarily close your laptop's lid without going into sleep mode. 

youtube-dl (how to) - best guide to get you started

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>> Installing

[Note]: Before you start; 

If you have upgraded to Catalina (on never have installed xcode and gcc before), then you will need to:

install Xcode (from Apple's App Store), then run the command: xcode-select --install 

then install gcc, and then install youtube-dl

[TIP]: You must run brew update first. Then you can either use the brew upgrade to update all packages, or, run brew upgrade youtube-dl to update only youtube-dl

//To install youtube-dl [1] under MacOS use:
brew install youtube-dl

//Once it is installed, update the application:
sudo youtube-dl -U

Ping an IP range from the command line interface (CLI)

If you ever wanted to do host discovery while no specific network scanning tools were available (e.g. nmap), or you wanted to avoid creating a script file (e.g. due to having no write permissions)? Here are a couple of useful commands depending on the OS of your choice:

Windows OS:
for /L %i IN (1,1,254) DO ping -n 1 -w 1 192.168.1.%i| FIND /i "Reply" >> IPs.txt

Note: command prompt has a limitation when asked to return the exact string using regex and returns the whole line. Here is an example of replacing find with findstr in order to use a regular expression (regex). 
findstr /r "[0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*"

The regular expression can still be useful in cases such as:
ipconfig | findstr /r "[0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*"


Linux OS:
for i in {1..254}; do (ping -c 1 -i 1 192.168.1.$i >/dev/null && echo "192.168.1.$i" &); done

Note: The above command will only list the discovered IP address, without any additional text.

Tip/Trick: Did you know you can use apr to achieve the same results but much faster. This seems to be reliable under Linux. The following command will list the discovered host on your network, including any additional information per IP (including the IPv6 address).
for ip in $(seq 1 254); do arp -n 192.168.1.$ip | grep on; done

The following command however, will list only the IP addresses without any additional text (also avoiding to specify the IP range twice)
for ip in $(seq 1 254); do arp -n 192.168.1.$ip | grep on | grep -Eo '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' ; done

Command line (CLI) check and monitor COVID-19 statistics

Use the following command to quickly check for COVID-19 (corona virus) statistics from the console (CLI), for the countries you want to monitor.

Command line:
clear && curl -s https://corona-stats.online/?minimal=true | grep "Rank\|(DE)\|(IT)\|(ES)\|(GR)\|(US)\|(AE)\|(GB)\|(CH)\|(AT)\|(NL)"

Modify the command as needed with any valid ISO 3166-1 Alpha-2 Country Codes. 

Thanks goes to @ekrysis for collecting the data sources and providing the means to query the information. See more at GitHub: https://github.com/sagarkarira/coronavirus-tracker-cli 

Some examples:
# Get data from worldometers api i.e source 2
curl https://corona-stats.online