CMD + , (comma) to quickly bring up advance settings in Safari to toggle dark mode

Reduce files of PDFs by a huge margin while maintaining acceptable image quality

Create your own filters using Color Sync Utility

open PDF - File | Export

select your custom filter

Mac OS
Screen Capturing

cmd + shift + 3 = captures whole screen
cmd + shift + 4 = captures selected region
cmd + shift + 4 + spacebar = captures window with camera icon

Use Preview as an image and PDF viewer. Basic image editing functions are Tools - Crop, Adjust Size to make the dimensions smaller, Export as jpg to reduce file size.

56Kbps = 7KB/s (dial up 1995, DSL 1997) 64Kbps = 8KB/s (ISDN) 128Kbps = 16KB/s (ISDN) 512Kbps = 64KB/s 1024Kbps = 128KB/s 3G (1,000Kbps) = 125KB/s 1.5Mbps = 188KB/s (some DSL & T1) 6Mbps = 800KB/s (cable and DSL) 10Mbps = 1.3MB/s (cable) 25Mbps = 3MB/s (cable) 50Mbps = 6MB/s (cable) 100Mbps = 12MB/s (fiber, 10/100Mbps ethernet) 1000Mbps = 120MB/s (if all switches, routers are gigabit ethernet)

USB 2.0 = 57MB/s WiFi 802.11b = 1.4MB/s WiFi 802.11g = 6.8MB/s WiFi 802.11n = 31MB/s

Regex (regular expressions)

([\d]+) remove all digits (numbers) 3453 peace 897 -----> peace

([^\d]+) remove everything except digits 5343 life -----> 5343

GREP (Global REplace and Print) command used in iThoughts app on iOS

m..n - Tamzin, Germaine, Tomlin, McEntire

m.n - Amanda, feminist, Minogue, Monaco

man$ - matches what ends in man Portman, Kidman, Chapman but NOT Amanda
sausage$ will match all text where the line ends with sausage ($ means 'end of line')

^ma - matches what starts in ma Mayor, May, Mary, Matt but NOT Pitman, Huma
^sausage will match all text where the line starts with sausage (^ means 'start of line')

sausage[1-3] will match on sausage1, sausage2, sausage3 but NOT sausage4.

[0-9] - only digits [A-Z] - only letters