UNIX for Advanced & Expert Users

echo "$1" |\
sed 's/./&\n/g' |\
awk '
        /[a-zA-Z]/ {a+=1}
        /[0-9]/    {n+=1}
        END{
                sum=a+n
                print sum,a,n
                if ( a == 0 && sum == NR-1 ) { print "numeric" }
                if ( n == 0 && sum == NR-1 ) { print "alpha" }
                else { print "something else" }
        }'

#!/bin/ksh

INPUT="ABC"

case $INPUT in
   ( +([0-9])       ) echo "$INPUT is all numbers" ;;
   ( +([a-zA-Z])    ) echo "$INPUT is all characters" ;;
   ( +([0-9a-zA-Z]) ) echo "$INPUT is alphanumeric" ;; 
   (               *) echo "$INPUT is something unknown" ;;
esac

exit 0

> cat test_alpha 
sample1="abcdef"
echo $sample1 - checking alpha
if [ $sample1 = `echo $sample1 | tr -d [0-9]` ]; then  echo "same"; fi

sample2="abc123def"
echo $sample2 - checking alpha
if [ $sample2 = `echo $sample2 | tr -d [0-9]` ]; then  echo "same"; fi

sample3="123456"
echo $sample3 - checking numeric
if [ $sample3 = `echo $sample3 | tr -d [:alpha:]` ]; then  echo "same"; fi

sample4="123abc456"
echo $sample4 - checking numeric
if [ $sample4 = `echo $sample4 | tr -d [:alpha:]` ]; then  echo "same"; fi

> test_alpha 
abcdef - checking alpha
same
abc123def - checking alpha
123456 - checking numeric
same
123abc456 - checking numeric

case $string in
  *[!0-9A-Za-z]*) echo "Not pure alpha + numbers" ;;
  *[!0-9]*) echo "Pure alpha";;
  '') echo "Empty string (duh)" ;;
  *) echo "Pure numbers" ;;
esac