Shell Programming and Scripting

filename.txt, filename.txt, alpha, nnnn, nnnn, nnnn, Free form text

case ${LINE} in
    # Expression 1..n are informational and specific enough that the
    # expressions work well
    expression 1..n)
             ... match expressions 1..n logic ... ;;

    # CSV lines contain 7 fields and 6 commas
    *,*,*,*,*,*,*)
         ... match valid CSV line logic ... ;;

    # Malformed CSV lines or any other not matching my list of expressions
    *)
         ... malformed CSV line or other mismatch ... ;;
esac

field1, field2, field3, field4, field5, field6, field7, field8, field9
field1, field2, field3, field4, field5, field6
field1, field2, field3, field4, field5, field6, field7,,,,,,,
,field1, field2, field3, field4, field5, field6, field7

case ...
...
    @(*)@(,)@(*) ) ...
...
esac

file1.txt, file1_original_name.txt, control1, 1001, 100001, 10000, Data Sample 1
file2.txt, file2_original_name.txt, control5, 2001, 100002, 10000, Data Sample 2
file3.txt, file3_original_name.txt, control7, 3001, 100003, 20000, Data Sample 3

#! /usr/bin/ksh

exec < data
while read line ; do
        case $line in
        +([_a-zA-Z0-9]).txt,+( )+([_a-zA-Z0-9]).txt,+( )+([a-zA-Z0-9]),+( )+([0-9]),+( )+([0-9]),+( )+([0-9]),* ) echo OK: $line
                ;;
        *)   echo XX: $line
                ;;
        esac
done
exit 0

file1.txt, file1_original_name.txt, control1, 1001, 100001, 10000, Data Sample 1,,,,,

+([_a-zA-Z0-9]).txt,+( )+([_a-zA-Z0-9]).txt,+( )+([a-zA-Z0-9]),+( )+([0-9]),+( )+([0-9]),+( )+([0-9]),+( )+([ a-zA-Z0-9]))

+([_a-zA-Z0-9]).txt,+( )+([_a-zA-Z0-9]).txt,+( )+([a-zA-Z0-9]),+( )+([0-9]),+( )+([0-9]),+( )+([0-9]),+( )+([!,])