Perl ABC

Read the entire contents of the file

How can I read the contents of a file in bulk with Perl? By convention, the contents of a file are often read at once, with the following description:

my $file = 'a.txt';
open my $fh, '<', $file
  or die "Can't open $file:$!";

# Read the contents of the file at once
my $content = do {local $/; <$fh>};

do block returns the last evaluated value.

local undefined predefined variable "$/" that represents a line break in the file.

This causes file input operator "<$fh>" to return the contents of the entire file.

And when the scope ends, "$/" returns to its original state.

Keep in mind that Perl, which doesn't have a builtin functions to read a file at once, may read the entire contents of the file in this way.