Regular expressions can be used to break up strings. This is what split does. The join function on the other hand takes a list of strings and combines them together again.

$line="Bart Lisa Maggie Marge Homer"; @simpsons=split(/\s/, $line); #splits $line and uses a piece of whites +pace as a delimiter. #@simpsons now contains ("Bart","","Lisa","Maggie","Marge","Homer"); #notice there is an extra space between Bart and Lisa so we get an emp +ty element in the array there. #lets try a better delimiter that will eliminate that from happening @simpsons=split(/\s+/ $line); #now splits $line on 1 or more whitespac +e characters #@simpsons now containts ("Bart","Lisa","Maggie","Marge","Homer");

Suppose we had a list of records of the form
Name|Phone Number|Address
We could open a file while which contained those records and do something like this:
open FILE, "data.txt"; while(<FILE>) chomp; ($name,$phone,$address)=split(/\|/); #splits the default variable $ +_ on | #notice we have to put \| sinc +e | is a metacharacter #that represents or. Otherwise + we'd be matching #empty string or empty string #then we place the results in +variables instead of a list #the parentheses around the va +riable names need #to be there for this to work +properly print "Name: $name\n"; #Now we print out the informat +ion in a more readable form print "Phone Number: $phone\n"; print "Address: $address\n\n"; } close FILE;

The function join can be used to reconstruct split up values into one string again. The syntax for calling this function is join($glue, @array) or join($glue,$var1,$var2....) The glue is simply the string that goes between two strings to hold them together. Here are a few examples:
$string=join(" ",@simpsons); #string now equals "Bart Lisa Maggie Marge Homer"; $name="Bob"; $phone="555-5555"; $address="42 Tulip Lane, Holland MI, 49423"; $string=join("|",$name,$phone,$address); #$string is now equal to "Bob|555-5555|42 Tulip Lane, Holland MI, 4942 +3"