Snippet for shell script with named arguments

dynamic_args.sh

#!/bin/bash

# FROM https://unix.stackexchange.com/a/388038

while [ $# -gt 0 ]; do
   if [[ $1 == *"--"* ]]; then
        v="${1/--/}"
        declare $v="$2"
   fi
  shift
done

shell_with_args.sh

#!/bin/bash

# FROM: https://unix.stackexchange.com/a/580258

while [ $# -gt 0 ]; do
  case "$1" in
    --days*|-d*)
      if [[ "$1" != *=* ]]; then shift; fi # Value is next arg if no `=`
      DAYS="${1#*=}"
      ;;
    --select*|-s*)
      if [[ "$1" != *=* ]]; then shift; fi
      SELECT="${1#*=}"
      ;;
    --help|-h)
      printf "Meaningful help message" # Flag argument
      exit 0
      ;;
    *)
      >&2 printf "Error: Invalid argument\n"
      exit 1
      ;;
  esac
  shift
done

echo "DAYS $DAYS - select $SELECT"