Bash Parameters and Variables

Internal

• bash Concepts
• bash Environment Variables

Global Variable

Global variables are only maintained within the context of the current shell. Once the shell exits, the global variables are discarded.

Global variables are not available to sub-shells,

export

export VAR=VALUE

Declaring a global variable to be exported causes the variable and its value to be copied in the environment of a invoked sub-shell. The sub-shell gets a copy of the variable, not a reference. Modifying the variable from the sub-shell does not reflect into the value of the global variable maintained by the invoking shell.

Local Variables

The local keyword designates a local variable. Local variables can only be declared inside a function.

Scope

All variables declared in a shell are visible inside the functions executed within that shell and inside functions invoked from function invoked from the shell, recursively.