Alias An abbreviation or an alternative name, usually mnemonic, for a command.
Function chaining The process of calling a function from another function.
Functions Provide a way of mapping a name to a list of commands. Functions are similar to subroutines and procedures in other programming languages.
Global scope If a variable has global scope, its value can be accessed from anywhere within a script.
Global variables Variables with global scope are referred to as global variables.
Local scope If a variable has local scope, its value can only be accessed within the function in which it is declared.
Local variables Variables with local scope are referred to as local variables.
Recursion A special instance of function chaining in which a function calls itself.
Return code The exit status from a function is called its return code. The convention for return codes is the same as for exit codes; 0 equals success and nonzero equals failure.
Scope Refers to the region within a program where a variable's value can be accessed.