[godelski]

  > Bash: ensure exactly two params are passed, 1st one is a dir, 2nd is a file, enter" than to type the code directly

This seems much simpler than you made it out to be. Why not use ${#FOO[@]} for the number of args.

If you have strict ordering, your program is just as fast to type as it is to ask cursor (imo)

  [[ $# == 2 && -d "$1" && -a "$2" ]] || exit 2

  alternatively conditionally assigning

  [[ $# == 2 && -d "$1" && -a "$2" ]] && PREFIX="$1" && FILE="$2" || exit 2

I'll give you that it is probably faster if you are wanting to write it more correct and be order invariant (not what you asked), but with boiler plate I often just use macros.

I'm curious, what is Cursor's solution? Here's a pretty quick way that leaves some room for expandablity

  #!/usr/bin/env bash
  
  declare -ri MAXARGS=2
  declare -rA ECODES=(
      [GENERAL]=1
      [BADARGS]=2
  )

  FILE=
  PREFIX=

  fail_with_log() {
      echo "$1"
      exit ${ECODES[$2]}
  }

  check_args() {
      [[ $# == $MAXARGS ]] \
          || fail_with_log "Wrong number of arguments, expected ${MAXARGS} got $#" "BADARGS"
  
      # We might want to use -f instead of -a 
      # Check if PREFIX + FILE or FILE + PREFIX
      if [[ -d "$1" && -a "$2" ]];
      then
          PREFIX="$1"
          FILE="$2"
      elif [[ -a "$1" && -d "$2" ]];
      then
          FILE="$1"
          PREFIX="$2"
      else
          fail_with_log "Must provide both a file and a directory" "BADARGS"
      fi 
  } 

  main() {
      check_args "$@"
      ...
  }

  main "$@" || exit ${ECODES["GENERAL"]}

I mean a bunch of stuff above are superfluous but it doesn't take long to write (can be macro'd) and that little bit adds some flexibility if we want to extend down the line. There's of course, many ways to write this too. We could use a loop to provide more extensibility or even more conditional assignments. But this feels clearer, even if not very flexible.

[jitl]

As I said, I know bash, I've been writing bash for 20 years. I often ask Cursor to write code because it's literally faster to type "cmd-k, ensure exactly two params are passed, 1st one is a dir, 2nd is a file, enter" then it is to type the code myself. It's like I'm programming with natural language rather than whatever programming language. Like a high level programming language, I decide what the program should do, and AI figures out how to do it. It's analogous to writing bash instead of c. I could write my scripts in c for MAXIMUM PERFORMANCE, but I don't because it's less convenient. I could write this snippet of bash myself, but I don't for same reason.

Re: macros: Cursor works this way as a shortcut for all manner of boring code in any programming language and for this kind of thing is very trustworthy. Using it leaves me more mental energy to spend on other things. Macros (I think I call this "snippets"?) are only worth it for frequently repeated tasks.

This is what that prompt produces. Besides putting the count check first, it's what I would have written myself:

    if [[ $# -ne 2 ]]; then
     echo "Error: Exactly 2 arguments required" >&2
     return 1
    fi

    if [[ ! -d "$1" ]]; then
     echo "Error: First argument must be a directory" >&2
     return 1
    fi

    if [[ ! -f "$2" ]]; then
     echo "Error: Second argument must be a file" >&2
     return 1
    fi

[godelski]

Sure, I mean it depends. If it doesn't matter I'd go with my one line. If it does matter then I find cursors solution insufficient.

I'm not trying to argue that it can't solve the issue, I'm just trying to say there's not a big difference between the number of characters in the solution to the number of characters in the question.

I believe you that you've been writing scripts for 20 years but at the same time with that experience you're probably aware of people with that much experience that still don't know how to write functions. I constantly see people do things right out of bash pitfalls ¯\_(ツ)_/¯