Menu
I'v always wondered what they're used for? Seems silly to put them in every time if you can never put anything inside them.
function_name () { #statements } Also is there anything to gain/lose with putting the function keyword at the start of a function?
function function_name () { #statements } 
475
Parentheses ( () ) are used to create a subshell. For example: $ pwd /home/user $ (cd /tmp; pwd) /tmp $ pwd /home/user. As you can see, the subshell allowed you to perform operations without affecting the environment of the current shell.
The empty parentheses are required in your first example so that bash knows it's a function definition (otherwise it looks like an ordinary command). In the second example, the () is optional because you've used function .
Similar to the let command, the (( ... )) construct permits arithmetic expansion and evaluation. In its simplest form, a=$(( 5 + 3 )) would set a to 5 + 3, or 8.
Generally, the -f command stands for files with arguments. The command specifies the associated input to be taken from a file or output source from a file to execute a program. The f command uses both -f and -F (follow) to monitor files. In a shell script, -f is associated with the specified filename.
The keyword function has been deprecated in favor of function_name() for portability with the POSIX spec
A function is a user-defined name that is used as a simple command to call a compound command with new positional parameters. A function is defined with a "function definition command".
The format of a function definition command is as follows:
fname() compound-command[io-redirect ...]
Note that the { } are not mandatory so if you're not going to use the keyword function (and you shouldn't) then the () are necessary so the parser knows you're defining a function.
Example, this is a legal function definition and invocation:
$ myfunc() for arg; do echo "$arg"; done; myfunc foo bar foo bar If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
