Rm is dangerous

A shell script's structure is lost without indentation, making it necessary to very carefully sort out its meaning. BTW your corrected script still doesn't have the indentation done properly -- here it is, correctly indented:

    #!/bin/bash
    # filename: trash-rm
    shopt -s extglob
    recursive=1
    declare -a cmd
    ((i = 0))
    for f in "$@"
    do
      case "$f" in
        (-*([fiIv])r*([fiIv])|-*([fiIv])R*([fiIv]))
        tmp="${f//[rR]/}"
        if [ -n "$tmp" ]
        then
          #echo "\$tmp == $tmp"
          cmd[$i]="$tmp"
          ((i++))
        fi
        recursive=0 ;;
        (--recursive) recursive=0 ;;
        (*)
        if [ $recursive != 0   -a  -d "$f" ]
        then
          echo "skipping directory: $f"
          continue
        else
          cmd[$i]="$f"
          ((i++))
        fi ;;
      esac
    done
    trash-put "${cmd[@]}"
    

The beautifier your chose failed to indent consistently -- note that the original doesn't consistently indent the block between "case" and "esac", among other errors.

This might sound like something trivial and after the fact, but beautifying can reveal logical errors that can escape the eye in a program listing that lacks indentation.

To force your beautifier to behave, temporarily comment out all cases of ";;", run the beautifier, then uncomment them.

> I found the script written by someone else ...

What? Your article doesn't say that. Please take some advice and give proper attribution for code that you include in an article but didn't write.