One of the details of OS X that you will always encounter, but which you might take for granted, is the blink rate of your text input cursor.
As you enter text, your cursor will flash off and on at a rate of once per second, which informs you that your cursor is active and ready to display any characters you type.
While one per second appears to be a command and accepted rate for this cursor, you might want to change this to have the cursor blink perhaps slightly faster, or slightly slower.
Unfortunately there is no quick system preference setting for adjusting the cursor blink rate in OS X, and while there may be third-party utilities that tap into the setting for this, as with many hidden settings you can change it directly using the “defaults” command in the OS X Terminal.
If you are running OS X 10.8 or earlier, then the command to run is the following, so copy and paste it into the Terminal, press Enter to execute it:
defaults write -g NSTextInsertionPointBlinkPeriod -float 1000
If you are running OS X 10.9 or later, then Apple has changed how the cursor blinking is set. Instead of having one setting dictate the entire period over which the cursor blinks, and then splitting the on-time and off-time for the cursor evenly for this period, Apple now has separate settings for the off and on times.
This allows you to set the cursor to have uneven off and on times, so you can better customize its behavior to your liking. The two commands to adjust how long the cursor stays on and off are the following:
defaults write -g NSTextInsertionPointBlinkPeriodOn -float 200 defaults write -g NSTextInsertionPointBlinkPeriodOff -float 200
In all of these commands, the number value is the delay time in milliseconds, so 1000 will represent one second.
To have the cursor blink faster, you will need to reduce this value, and to make it blink slower, increase this value. I recommend you try values of 200 to 2000 to see how these make the cursor behave with respect to the default value (1000 for the first command, and 500 for both the second commands), but then give intermediate values a try.
Of course this is your text cursor, but you can change its blink rate, if you would like.
When you have made these changes, you will need to quit and re-launch your applications for the changes to take effect, and in some cases you might need to log out and back into your account. Also note that this will only work for applications and text fields that are coded with Apple’s text view coding objects, so programs that use alternative text handling routines may not show a difference in blink rate.
If you want to revert any of the changes you have made to the cursor blink rate, simply re-run the command above, and use 1000 as its value, or you can optionally delete the custom settings entry by running the following commands, and OS X will then use its default built-in value:
defaults delete -g NSTextInsertionPointBlinkPeriod defaults delete -g NSTextInsertionPointBlinkPeriodOn defaults delete -g NSTextInsertionPointBlinkPeriodOff