PHP Questions

Permissions in PHP are very similar to UNIX. Each file has three types of permissions – Read, write and execute. Permissions can be changed using the change mode or CHMOD command. CHMOD is followed by 3 digit number specifying the permission type. CHMOD 777 is for Read, Write and execute.

Unnecessary permissions can be stripped off using UNMASK command.

Unmask (777);

Notices, Warnings and Fatal errors are the types of errors in PHP

Notices: 

Notices represents non-critical errors, i.e. accessing a variable that has not yet been defined. By default, such errors are not displayed to the user at all but whenever required, you can change this default behavior.

Warnings: 

Warnings are more serious errors but they do not result in script termination. i.e calling include() a file which does not exist. By default, these errors are displayed to the user.

Fatal errors: 

Fatal errors are critical errors i.e. calling a non-existent function or class. These errors cause the immediate termination of the script.

The mail() function of PHP is quite robust for sending bulk emails. A SMTP server can also be directly used from the script. PHPmailer class can be used for sending emails.

PEAR(PHP Extension and Application Repository) is a framework and repository for reusable PHP components. PEAR is a code repository containing all kinds of php code snippets and libraries. 

PEAR also offers a command-line interface that can be used to automatically install "packages".

strstr() returns part of a given string from the first occurrence of a given substring to the end of the string.
For example:
strstr("user@example.com","@") will return "@example.com".

stristr() is idential to strstr() except that it is case insensitive.