Format and print text. More information: https://www.gnu.org/software/coreutils/printf.
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
printf "hex=%x octal=%o scientific=%e" 0xFF 0377 100000