使用getopts传递给函数时，命令行参数不起作用

Question

I've been trying to get some practice in with bash shell scripting but I've been having trouble using the $1 variable to reference the first argument for my script. It's a simple script that takes a file as an argument and prints the name of the file. Here's my script:

#!/bin/bash

function practice() {
  echo "${1}"
}

while getopts "h:" opt; do
  case "$opt" in
  h) practice
     ;;
  esac
done

exit 0

I tried the following command:

./practice.sh -h somefile.txt

For some reason it returns an empty line. Any thoughts?

Answer 1

$1 in functions refers to first positional parameter passed to that function, not passed to your script.

Therefore, you have to pass the arguments you want to the function again. You also tell getopts you want to process -h but then you are checking for -a in your case instead:

#!/bin/bash

practice() {
   echo "${1}"
}

while getopts "h:" opt; do
  case "$opt" in
     h) practice "${OPTARG}"
        ;;
  esac
done

Answer 2

#!/bin/bash

function practice() {
    echo "${1}"
}

 while getopts "h:" opt; do
  case "$opt" in
  a) practice $*
    ;;
  esac
 done

exit 0

pass the command line arguments to the function as above.