if判断变量为字母或者数字

网上搜罗而来，验证可用

#! /bin/bashprintf "Enter: "read var   if [[ $var =~ ^[0-9]+$ ]]      then          echo "Number."     elif [[ $var =~ ^[A-Za-z]+$ ]]      then           echo "String."     else           echo "mixed number and string or others "
    fi  
或者 awk or gawk#! /bin/bashprintf "Enter: "read var   echo "$var" | gawk '{          if ($0 ~ /^[0-9]+$/){                 print "Number "          } else if ($0 ~ /^[A-Za-z]+$/){                 print "String "          } else {                 print "Mixed number and string or others"          }   }'