Which command creates a local variable inside a Bash function?

• A. export bob
• B. local bob
• C. declare -g bob
• D. setlocal bob

Answer: (B)

Inside a Bash function, creating a variable that stays confined to that function uses the local builtin. It declares the variable with function scope, so it exists only while the function runs and its value won’t leak into the surrounding script once the function returns. This is what gives you clean isolation of data inside the function.

Export, on the other hand, marks a variable to be part of the environment for the current shell and any child processes, which makes it global rather than local to the function. The declare command can set up variables and, with the -g flag, makes a global variable instead of local to the function. Setlocal isn’t a Bash builtin, so it isn’t used for this purpose.

So the method to create a local variable inside a Bash function is to use the local command, for example: local bob.