#mode operand create truncate
#read<
#write> yes yes
#append>> yes
Case 1: Throw an exception if you cannot open the file:
复制代码 代码如下:
use strict;
use warnings;
my $filename = \’data.txt\’;
open(my $fh, \'<:encoding(UTF-8)\’, $filename)
or die \”Could not open file \’$filename\’ with the error $!\”;
while (my $row = <$fh>) {
chomp $row;
print \”$row\\n\”;
}
close($fh);
Case 2: Give a warning if you cannot open the file, but keep running:
复制代码 代码如下:
use strict;
use warnings;
my $filename = \’data.txt\’;
if (open(my $fh, \'<:encoding(UTF-8)\’, $filename)) {
while (my $row = <$fh>) {
chomp $row;
print \”$row\\n\”;
}
close($fh);
} else {
warn \”Could not open file \’$filename\’ $!\”;
}
Case 3: Read one file into array
复制代码 代码如下:
use strict;
use warnings;
my $filename = \’data.txt\’;
open (FILEIN, \”<\”, $filename)
or die \”Could not open file \’$filename\’ with the error $!\”;
my @FileContents = <FILEIN>;
for my $l (@FileContents){
print \”$l\\n\”;
}
close FILEIN;
end
