substr EXPR,OFFSET,LENGTH,REPLACEMENT
       substr EXPR,OFFSET,LENGTH
       substr EXPR,OFFSET
               Extracts a substring out of EXPR and returns it.
               First character is at offset 0, or whatever you've
               set $[ to (but don't do that).  If OFFSET is nega-
               tive (or more precisely, less than $[), starts
               that far from the end of the string.  If LENGTH is
               omitted, returns everything to the end of the
               string.  If LENGTH is negative, leaves that many
               characters off the end of the string.

               You can use the substr() function as an lvalue, in
               which case EXPR must itself be an lvalue.  If you
               assign something shorter than LENGTH, the string
               will shrink, and if you assign something longer
               than LENGTH, the string will grow to accommodate
               it.  To keep the string the same length you may
               need to pad or chop your value using "sprintf".

               If OFFSET and LENGTH specify a substring that is
               partly outside the string, only the part within
               the string is returned.  If the substring is
               beyond either end of the string, substr() returns
               it.  To keep the string the same length you may
               need to pad or chop your value using "sprintf".

               If OFFSET and LENGTH specify a substring that is
               partly outside the string, only the part within
               the string is returned.  If the substring is
               beyond either end of the string, substr() returns
               the undefined value and produces a warning.  When
               used as an lvalue, specifying a substring that is
               entirely outside the string is a fatal error.
               Here's an example showing the behavior for bound-
               ary cases:

                   my $name = 'fred';
                   substr($name, 4) = 'dy';            # $name is now 'freddy'
                   my $null = substr $name, 6, 2;      # returns '' (no warning)
                   my $oops = substr $name, 7;         # returns undef, with warning
                   substr($name, 7) = 'gap';           # fatal error

               An alternative to using substr() as an lvalue is
               to specify the replacement string as the 4th argu-
               ment.  This allows you to replace parts of the
               EXPR and return what was there before in one oper-
               ation, just as you can with splice().

Ja, noch sehr un-deutsch...

-- RelaiS - 23 Aug 2003