What's the best practice in capitalization and punctuation when outputting program progress to STDERR?

I'm making some command line tools that output progress information as it runs to STDERR, like

found document
using cached version
analyzing

etc.

Should I output full sentences with capitalized first letters 开发者_StackOverflow中文版and periods at the end, or is this kind of terse uncapitalized output OK? What's the expert consensus on this?

My favorite method to denote progress is a 'spinner'. Here is one I implemented using bash. The first parameter is the PID of the process you want to track and the second parameter is an optional message. The PID is most easily passed via $(pgrep <some_process_name>)

#!/bin/bash

spinner() {
  [[ -n "$2" ]] && echo -n "$2 "

  if [[ ! $1 =~ ^[[:digit:]]+$ ]]; then
    return
  fi

  while [[ -d /proc/$1 ]]; do
    for c in '/' '-' '\' '|'; do
      printf "%c\b" "$c"
      sleep 0.1
    done
  done
  printf " \n"
}

du /usr > /dev/null 2>&1 & # Example program to monitor
spinner $(pgrep du) "Optional Message Here"