Halt and Catch Fire (2014 - 2017)

If key presses are slow or laggy, check the system configuration, for example on Ubuntu you can configure keyboard repeat interval and delay:

gsettings set org.gnome.desktop.peripherals.keyboard repeat-interval 3
gsettings set org.gnome.desktop.peripherals.keyboard delay 150

On KDE you can open a window to change the ‘Delay’ and ‘Rate’:

systemsettings5 kcm_keyboard

On OSX, if holding down a key does not repeat the command (a feature of OSX), you make a key repeat by running this once at the terminal:

defaults write com.sublimetext.3 ApplePressAndHoldEnabled -bool false

In general if you are on X11 type systems you could directly use:

xset r rate <milliseconds_before_repeating> <repetitions_per_second>

Ubuntu

You can adjust the delay and repeat interval via the Settings GUI.

Settings → Universal Access → Typing → Repeat Keys

Ubuntu Univeral Access Typing

Adjust the delay and speed to taste.

Ubuntu Univeral Access Typing

To script it use gsettings.

gsettings set org.gnome.desktop.peripherals.keyboard delay 150
gsettings set org.gnome.desktop.peripherals.keyboard repeat-interval 3