Question

Write a script that accepts a single character argument (command line parameter), then checks to see if the argument is an upper- or lower-case letter. (You do not have to do any error checking. Just assume that the user will enter a single character.) Hint: use grep to search for a member of the character class [a-z]. Then use the exit code (in an if statement) to see if grep was successful and write the proper response. If the argument is a letter, print (display to screen) “You entered a letter.” If the argument is not a letter, print “You did not enter a letter.”

Answer 1

letter.sh:

   #reads a command lone argument and checks for a upper-case or lower-case letter
   if grep -q "[a-zA-Z]" <<< "$1"
   #if block
   then
       #prints output if it is a letter
       echo "You entered a letter"
       #exit code for if statement
       exit 1
   #else block
   else
       #printf otput if the character is not a letter
       echo "You did not enter a letter"
   fi #end of if block

      

Output: