Shell Programming and Scripting

 
echo -n "Enter Author:"
read Author
#echo -n "Enter Title:"
#read Title
 
if [[$Author = [a-z] ] ; then
echo "you enter something"
else 
echo " you enter nothing"
fi

./Search: line 29: [[a: command not found

$ Author=b ; if [[ $Author = [a-z] ]]; then echo hello; fi
hello

if ! [[ $Author = *[^a-z]* ]]; then 
  echo hello
fi

case $Author in 
  *[^a-z]*) echo wrong ;;
         *) echo right ;; 
esac

if [ -n "$Author" ]; then
  echo not empty
fi

echo -n "Enter Author: " ; read Author
if [ ${#Author} -le 3 ]
then
  echo "Full name, please!"
fi

if [ -n "$Author" ]; then
  echo not empty
fi

[-n: command not found

f [  -n "$Author" ] | [  -n "$Title" ] ; then
  echo "you enter something"
else 
echo " you enter nothing"
fi