Format and print text.
printf {{"%s\n"}} {{"Hello world"}}
printf {{"\e[1;34m%.3d\e[0m\n"}} {{42}}
printf {{"\u20AC %.2f\n"}} {{123.4}}
printf {{"var1: %s\tvar2: %s\n"}} {{"$VAR1"}} {{"$VAR2"}}
printf -v {{myvar}} {{"This is %s = %d\n" "a year" 2016}}