Line = 'org_name,"My Organization"' 
Field = 'org_name 
' 
Field Length = 9 
Trim Length = 'org_name 
' 

Line ($line) is a string to which I want to compare some key words. 

Field ($field) is one of the key words. I have placed single quotes around the value so I can see its length. 

Field Length ($length) is the result of the Perl length($field) function. 

Trim Length ($trim_length) is the result of substr ($field, 0, $length). 

$field is read from a database table using the @fields = qx{query}; 

The relationship between @fields and $field comes from a foreach @field (@fields) loop.