# simple shell script

#!/bin/bash
groupadd students
for i in {1..20}
do
  useradd stu$i
  if [ $? -eq 0 ];then
    echo -e "add user stu$i\n"
  else
    echo -e "add user stu$1 failed\n"
  fi
done

#!/bin/bash
printf "Decimal\tHex\tCharactor\n"
printf "-------------------------\n"
for i in {33..126}
do
  printf "%d\t%x\t" $i $i
  printf \\$(printf "%03o" $i)
  printf "\n"
done