wexec - shell function to allow easy iteration on a shell command, uses watchexec to re-run a command whenever the file is saved

wexec.zsh

# add to your .zshrc/.bashrc

# sets up "live reload"-like environment for for a single file
# will watch a file (create it if it doesn't exist), every time it is saved it will run a command

EDITOR=mvim # I use MacVim but switch this to whatever you use (something that'll be outside of the same terminal window)

function wexec() {
  command -v watchexec >/dev/null 2>&1 || { echo "'watchexec' is required. e.g. brew install watchexec or cargo install watchexec" >&2; exit 1; }
  if [[ -z $1 || "$1" == "--help" ]]; then
    echo "usage: "
    echo "    wexec <file/command to watch>"
    echo "        the file will be assumed to be an executable command that will be run"
    echo "        when it changes"
    echo ""
    echo "          ex: wexec foo.sh"
    echo ""
    echo "        the file will be created and marked as executable if it does not exist"
    echo "or:"
    echo ""
    echo "    wexec <file/command to watch> <command args to run when file is changed>"
    echo ""
    echo "          ex: wexec yolo.sql psql -f yolo.sql"
    echo ""
    return -1
  fi

  FILE=$1

  if [[ -z $2 ]]; then
    # if no further commands are passed, then the file is the command
    COMMAND="./$FILE"

    if [ ! -f $FILE ]; then
      # create the file as it doesn't exist, make it executable as it is the command
      touch "$FILE"
      chmod +x "$FILE"
    fi
  else
    if [ ! -f $FILE ]; then
      # create the file as it doesn't exist, don't make it executable, it is not the command
      touch "$FILE"
    fi

    # all the args after the first are the command to run
    COMMAND="${@:2}"
  fi

  # open the file in an editor for changes
  $EDITOR "$FILE"

  bash -c "watchexec -s SIGINT -r -d 100 -f '*/$FILE' '$COMMAND'"

}