The \s metasymbol and whitespace

    
while(<DATA>){
    print if s/\s/*/g; # Substitute all spaces with stars
}
__DATA__
    A 101
    A A A

1.	The e Modifier Evaluating an Expression
2.	The e modifier
3.	The g Modifier Global Substitution
4.	The m Operator and Matching
5.	The m modifier controls the behavior of the $ and ^ anchor metacharacters.
6.	The s Modifier-The Dot Metacharacter and the Newline
7.	The s Operator and Substitution
8.	The s operator supports a number of variables
9.	The x Modifier: The Expressive Modifier
10.	The i Modifier Case Insensitivity
11.	\B matches only if the pattern is contained in a word.
12.	ei modifier
13.	Use /gc to remember position
14.	Use \G to match rest of text
15.	The \S metasymbol and nonwhitespace
16.	Matching Modifiers
17.	Inline Modifiers

The \s metasymbol and whitespace : modifier « Regular Expression « Perl