Errata

The paragraph with the mistake: But if you (or a program) may be waiting impatiently for the output, you may wish to take that performance hit and flush the output buffer each time you print. See $! in the perlvar documentation for more information on controlling buffering in that case. There is most likely a typo -- the $! is variable which contains recent errno value, while output autoflush control variable is a $| Source: perldoc ( https://perldoc.perl.org/perlvar#$%7C and https://perldoc.perl.org/perlvar#$! )

Note from the Author or Editor:
Change as noted. The $! should be $|

Perl.org have upgraded to more secure connection. Correct address: https://learn.perl.org/

Note from the Author or Editor:
Update "http://learn.perl.org" to be "https://learn.perl.org", including the link

$rock_fh --> $rocks_fh

Note from the Author or Editor:
In the last line on the page, change $rock_fh to $rocks_fh

$rock_fh --> $rocks_fh

Note from the Author or Editor:
In the first line on the page, change $rock_fh to $rocks_fh

"Found a URL\n" --> "Found a .png\n"

Note from the Author or Editor:
In the second code block, change if ( /\.png\z/ ) { print "Found a URL\n"; } to if ( /\.png\z/ ) { print "Found a PNG\n"; }

First comment should be "one or more digits" instead of "one or more digits before the decimal point"

Note from the Author or Editor:
In this example / [0-9]+ # one or more digits before the decimal point [#] # literal pound sign /x Change as noted to / [0-9]+ # one or more digits [#] # literal pound sign /x

"the pattern /\.old$/" was not updated to corresponding "/\.old\z/" showed in the code example.

Note from the Author or Editor:
In the last paragraph, change: So you use the pattern /\.old$/ to mean to So you use the pattern /\.old\z/ to mean

it could be better to add the comment "# or Ctrl-Z" for people who use Windows.

Note from the Author or Editor:
In the two code lines on that page that are: print "Enter some lines, then press Ctrl-D:\n"; we can change that to print "Enter some lines, then press Ctrl-D:\n"; # or Ctrl-Z on Windows

Perlbrew have upgraded to more secure connection. Correct address: https://perlbrew.pl

Note from the Author or Editor:
Change URL to have https

= (binding operator) seems typo Correct one: =~ (binding operator)

Note from the Author or Editor:
Correct as noted.

Typo: qw()() Correct one: qw()

Note from the Author or Editor:
In that index entry, there should be only one set of parentheses.