Bash Reference Manual. Node: Shell Operation
 
Shell Syntax
Quoting
3.1.1: Shell Operation
The following is a brief description of the shell's operation when it
reads and executes a command.  Basically, the shell does the
following:
- 
Reads its input from a file (see Shell Scripts), from a string
supplied as an argument to the `
-c' invocation option
(see Invoking Bash), or from the user's terminal.
 - 
Breaks the input into words and operators, obeying the quoting rules
described in Quoting.  These tokens are separated by
metacharacters.  Alias expansion is performed by this step
(see Aliases).
 - 
Parses the tokens into simple and compound commands
(see Shell Commands).
 - 
Performs the various shell expansions (see Shell Expansions), breaking
the expanded tokens into lists of filenames (see Filename Expansion)
and commands and arguments.
 - 
Performs any necessary redirections (see Redirections) and removes
the redirection operators and their operands from the argument list.
 - 
Executes the command (see Executing Commands).
 - 
Optionally waits for the command to complete and collects its exit
status (see Exit Status).
 
 
Shell Syntax
Quoting