Re: \s matches newline in regex?

It seems like \s is matching the newline character,

Yes.

Tip #9 from the Basic debugging checklist: YAPE::Regex::Explain

The regular expression:

(?-imsx:Hi\s*)

matches as follows:
  
NODE                     EXPLANATION
----------------------------------------------------------------------
(?-imsx:                 group, but do not capture (case-sensitive)
                         (with ^ and $ matching normally) (with . not
                         matching \n) (matching whitespace and #
                         normally):
----------------------------------------------------------------------
  Hi                       'Hi'
----------------------------------------------------------------------
  \s*                      whitespace (\n, \r, \t, \f, and " ") (0 or
                           more times (matching the most amount
                           possible))
----------------------------------------------------------------------
)                        end of grouping
----------------------------------------------------------------------
[download]

This works for your simple input:

$line =~ s/Hi[^\n]*//;
[download]

Comment on Re: \s matches newline in regex? Select or Download Code

Replies are listed 'Best First'.
Re^2: \s matches newline in regex? by Only1KW (Sexton) on Jul 22, 2015 at 16:49 UTC
So if \s matches more than a space, how do I match just a space? While I agree your suggestion works for my simple example, it won't work for my actual workload.	[reply]
Re^3: \s matches newline in regex? by Corion (Patriarch) on Jul 22, 2015 at 17:04 UTC
You can use `[ ]`, or `\x{20}` or `\U{0020}` I guess.	[reply] [d/l] [select]
Re^3: \s matches newline in regex? by GrandFather (Saint) on Jul 22, 2015 at 20:58 UTC
If you want just a space use just a space! If you want to match everything except some specific white space characters use a negated character class with \S and the other white space characters you want to keep: `s/Hi[^\S\n\r\f]+//g` for example. Premature optimization is the root of all job security	[reply] [d/l]