Understanding where the PHP interpreter's file
access permissions come from.
Reading entire local and remote files with
Writing entire local and remote files with
Opening and closing files with fopen( ) and
Reading a line of a file with fgets( ).
Using feof( ) and a for( ) loop
to read each line in a file.
Using forward slashes in filenames with all operating systems.
Providing different file modes to fopen( ).
Writing data to a file with fwrite( ).
Reading a line of a CSV file with fgetcsv( ).
Determining whether a file exists with file_exists(
Inspecting file permissions with is_readable( )
and is_writeable( ).
Checking for errors returned from file access functions.
Understanding when to check a return value with the identical
operator (= = =).
Removing potentially dangerous parts of externally supplied filenames.