Perl Study Notes (v)--input and output

File handle

The file handle (filehandle) is the name of the application that represents the I/O connection between the Perl process and the outside world. is not the name of the file.

Open File Handle

Default file handles provided by Perl: STDIN, STDOUT, STDERR

   Open CONFIG, ' Dino ';                # Open the config file handle and point it to Dino   Open CONFIG, ' <dino ';              # Ibid., read-only open   Open Bedrock, ' >fred ';           # Open file handle bedrock and output to new file Fred   Open LOG, ' >>logfile ';               # Open File in Append mode

Specify how data is encoded

Open CONFIG, ' <:encoding (utf-8) ', ' Dino ';

Write data to a file with a specific encoding

Open Bedrock, ' >:encoding (utf-8$file _name;

Close file handle

Close Bedrock;

with die Handling Fatal Errors

1 if (! Open LOG , ">>",' logfile ') {2die           "Cannot create logfile:$!";                  # $! is a readable system error message 3 }

Using die will automatically append the Perl program name and line number after the error message, if you do not want to be able to add a newline character \ n Remove

Automatic detection of fatal errors　　

1  use Autodie;

with say to Output

The function is similar to the print function, but automatically adds a line break when each line of content

Perl Study Notes (v)--input and output