Bash Function: Find Number Of Arguments Passed

To find the number of arguments passed to a Bash function, you can use the $# special parameter.

The $# special parameter expands to the number of positional parameters passed to the function. It is updated each time the function is called, and its value corresponds to the number of arguments passed to the function.

Here is an example of how you can use the $# special parameter to find the number of arguments passed to a Bash function:

# Define the function
my_function() {
  # Print the number of arguments
  echo "Number of arguments: $#"
}

# Call the function with different numbers of arguments
my_function
my_function arg1
my_function arg1 arg2
my_function arg1 arg2 arg3

This will output the following:

Number of arguments: 0
Number of arguments: 1
Number of arguments: 2
Number of arguments: 3

Note that the $# special parameter only counts the number of positional parameters, and does not include options or flags passed to the function. To count these as well, you can use the $@ special parameter and check the length of the resulting array.

For example:

# Define the function
my_function() {
  # Count the number of arguments, including options and flags
  num_args=${#@}

  # Print the number of arguments
  echo "Number of arguments: $num_args"
}

# Call the function with different numbers of arguments
my_function
my_function arg1
my_function arg1 arg2
my_function --option arg1
my_function -f --option arg1
my_function -f --option arg1 arg2

This will output the following:

Number of arguments: 0
Number of arguments: 1
Number of arguments: 2
Number of arguments: 2
Number of arguments: 3
Number of arguments: 4

Overall, the $# special parameter is a useful tool for finding the number of arguments passed to a Bash function. It allows you to easily determine the number of arguments and perform tasks based on the number of arguments.