string operation

i am new user of unix.i have a question.My script is-

export STR_ALFA=`head -2 "${FILE_PATH}"|tail -1|cut -d"," -f1`
"${TEST_HOME}"/function/chk_alfa.ksh STR_ALFA

now i want to check STR_ALFA:

1)whether is alphabetic
2)whether is numeric
3)whether is alphanumeric
-------------------------------
please provide me necessary code to check this.please provide 4 code[/b]

No duplicate or cross-posting, please read the rules.

Continue here:

http://www.unix.com/shell-programming-scripting/68847-string-operation.html\#post302204267

Thread closed.