open

open

open FILEHANDLE,EXPR

open FILEHANDLE,MODE,EXPR

open FILEHANDLE,MODE,EXPR,LIST

open FILEHANDLE,MODE,REFERENCE

open FILEHANDLE

Opens the file whose filename is given by EXPR, and associates it with FILEHANDLE.

Simple examples to open a file for reading:

   open(my $fh, "<", "input.txt") 
or die "cannot open < input.txt: $!";

and for writing:

   open(my $fh, ">", "output.txt") 
or die "cannot open > output.txt: $!";

(The following is a comprehensive reference to open(): for a gentler introduction you may consider perlopentut.)

If FILEHANDLE is an undefined scal