put it in ~/Library/KeyBindings on Mac systems

DefaultKeyBinding.dict

{
  "~P" = (insertText:, "Π");
  "~s" = (insertText:, "ş");
  "~S" = (insertText:, "Ş");
  "~k" = (insertText:, "ı");
  "~K" = (insertText:, "İ");
  "~g" = (insertText:, "ğ");
  "~G" = (insertText:, "Ğ");
  "~l" = (insertText:, "λ");
  "~L" = (insertText:, "Λ");
  "~o" = (insertText:, "ω");
  "~a" = (insertText:, "α");
  "~b" = (insertText:, "β");
  "~d" = (insertText:, "δ");
  "~D" = (insertText:, "Δ");
  "~h" = (insertText:, "γ");
  "~h" = (insertText:, "Γ");
}