Are each of the fields of a fixed length? That is, does the field you wish to isolate always start at character 7 of the line, and is it always 10 characters long?

If so, read up on the substr function.

In substr you can't specify "Start from character 7 and continue until you find a blank space", right? Or can you?

But you could read from character 7 till the end, and then use split to get the part before the first whitespace ...

... or use index to search for the first blank after position 7, and adjust your substr accordingly ...

so many possibilities ;-)

1. Regular expressions; obviously, this is out based on the spec. It's possible however that the intent is to use split, which might not be considered a regular expression for the purposes of your assignment. Split on \s+, and the second term is your target.

2. unpack works for fixed-width formats, which this appears to be. Your template would consist of a series of A#, where each # would be the appropriate field width. The results will truncate trailing whitespace automatically. Again, grab the second term.

3. substr and index. This could work for either fixed-width fields or variable width fields. The most obvious choice would be to grab from the 6th character on, use index on the result to find the first space, and then truncate in a second step.

The split function seems the simplest approach to me:

#! /usr/bin/perl

while(<DATA>) {
   my @field = split " ", $_;
   print "Field 2 => ",$field[1], "\n";
}
__DATA__
ID   SP96_DICDI     STANDARD;      PRT;   600 AA.
[download]

And the output is:

C:\scripts>perl field_split.pl
Field 2 => SP96_DICDI
[download]

Thanks so much guys!
I think I will (must) go with susbtr, because, technically, we don't "know" regexps and arrays yet!