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
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please provide me necessary code to check this.[/b]please provide 4 code

What have you done to attempt to solve this problem yourself?
Post your sample script, and we'll see how we can assist.