Angle brackets <> can be used for simple line input. In scalar context, they return the next line; in list context, all remaining lines; the default filehandle is STDIN or any files mentioned in the command line (ie @ARGV).
Angle brackets can also be used as a globbing operator if anything other than a filehandle name appears between the angle brackets. In scalar context, returns the next file matching the glob pattern; in list context, returns all remaining matching files.
The open() and close() functions can be used to open and close files. Files can be opened for reading, writing, appending, read/write, or as pipes.
The opendir(), readdir() and closedir() functions can be used to open, read from, and close directories.
The File::Find module can be used to recurse down through directories.
File test operators or stat() can be used to find information about files
File locking can be achieved using flock()
Binary data can be read using the read() function. The binmode() function should be used to ensure platform independence when reading binary data.