What does the built-in Mapfile do in bash?

What does the built-in Mapfile do in bash?

On Unix-like operating systems, mapfile is a builtin command of the Bash shell. It reads lines from standard input into an indexed array variable. For more information about bash array variables, see arrays in bash.

What is a built-in command in Linux?

Linux built-ins are commands that are part of a user’s shell. Built-ins are used just like other Linux commands. They are likely to run a bit faster than similar commands that are not part of your shell. Bash built-ins include commands such as alias, export and bg.

What can you do with a builtin function in Bash?

Similar to the way you would want to change the default behavior of an external command like curl in bash, builtin allows you to work around the case that you have declared a function with the same name as declare. In addition to allowing you to run builtin commands directly, it can be used to test if a name is a builtin.

When to use the builtin command in Linux?

builtin command in Linux with examples Last Updated : 15 May, 2019 builtin command is used to run a shell builtin, passing it arguments (args), and also to get the exit status. The main use of this command is to define a shell function having the same name as the shell builtin by keeping the functionality of the builtin within the function.

Why are there so many commands in Bash?

Bash has several commands that comes with the shell (i.e built inside the bash shell). When you execute a built-in command, bash shell executes it immediately, without invoking any other program. Bash shell built-in commands are faster than external commands, because external commands usually fork a process to execute it.

When to use shell builtin in a shell function?

This is useful when defining a shell function with the same name as a shell builtin, retaining the functionality of the builtin within the function. The return status is non-zero if shell-builtin is not a shell builtin command. Returns the context of any active subroutine call (a shell function or a script executed with the . or source builtins).