unbound variable when run a crontab task in mac os x - macos

Question

when I run script in mac os x like this:
*/1 * * * * /Users/dolphin/Library/"Mobile Documents"/com~apple~CloudDocs/Document/source/dolphin/dolphin-scripts/bash/cron/latex_compile_alive_monitor.sh >> /Users/dolphin/shell.log
the output is:
From dolphin#dolphins-MacBook-Pro.local Tue Jan 21 20:47:01 2020
Return-Path: <dolphin#dolphins-MacBook-Pro.local>
X-Original-To: dolphin
Delivered-To: dolphin#dolphins-MacBook-Pro.local
Received: by dolphins-MacBook-Pro.local (Postfix, from userid 501)
id 7430417C4C19; Tue, 21 Jan 2020 20:47:00 +0800 (CST)
From: dolphin#dolphins-MacBook-Pro.local (Cron Daemon)
To: dolphin#dolphins-MacBook-Pro.local
Subject: Cron <dolphin#dolphins-MacBook-Pro> /Users/dolphin/Library/"Mobile Documents"/com~apple~CloudDocs/Document/source/dolphin/dolphin-scripts/bash/cron/latex_compile_alive_monitor.sh >> /Users/dolphin/shell.log
X-Cron-Env: <SHELL=/bin/sh>
X-Cron-Env: <PATH=/usr/bin:/bin>
X-Cron-Env: <LOGNAME=dolphin>
X-Cron-Env: <USER=dolphin>
X-Cron-Env: <HOME=/Users/dolphin>
Message-Id: <20200121124701.7430417C4C19#dolphins-MacBook-Pro.local>
Date: Tue, 21 Jan 2020 20:47:00 +0800 (CST)
+ BOOK_PATH='/Users/dolphin/Library/Mobile Documents/com~apple~CloudDocs/Document/source/dolphin/summary/'
+ COMMAND='/Library/TeX/texbin/latexmk -pdfxe -pvc -xelatex -interaction=nonstopmode '
+ PROCESS_NAME_KEYWORDS_MAP=(["dolphin-book-2020.tex"]="${COMMAND} ./dolphin-book-2020/dolphin-book-2020.tex" ["the-book-of-mine.tex"]="${COMMAND} ./the-books-of-mine/the-book-of-mine.tex" ["kubelet-learn.tex"]="${COMMAND} ./kubelet-learn/kubelet-learn.tex")
/Users/dolphin/Library/Mobile Documents/com~apple~CloudDocs/Document/source/dolphin/dolphin-scripts/bash/cron/latex_compile_alive_monitor.sh: line 15: dolphin: unbound variable
which variable was unboud? COMMAND? I am already defined in script.this is my script:
#!/usr/bin/env bash
# 当使用未初始化的变量时，程序自动退出
set -u
# 当任何一行命令执行失败时，自动退出脚本
set -e
# 在运行结果之前，先输出执行的那一行命令
set -x
BOOK_PATH="/Users/dolphin/Library/Mobile Documents/com~apple~CloudDocs/Document/source/dolphin/summary/"
COMMAND="/Library/TeX/texbin/latexmk -pdfxe -pvc -xelatex -interaction=nonstopmode "
declare -A PROCESS_NAME_KEYWORDS_MAP=(
["dolphin-book-2020.tex"]="${COMMAND} ./dolphin-book-2020/dolphin-book-2020.tex"
["the-book-of-mine.tex"]="${COMMAND} ./the-books-of-mine/the-book-of-mine.tex"
["kubelet-learn.tex"]="${COMMAND} ./kubelet-learn/kubelet-learn.tex"
)
cd "${BOOK_PATH}"
for key in ${!PROCESS_NAME_KEYWORDS_MAP[#]}
do
PID_COUNT=`ps -ef | grep "${key}" | grep -v "grep" | wc -l`
if [[ ${PID_COUNT} -lt 1 ]]; then
nohup `${PROCESS_NAME_KEYWORDS_MAP[${key}]}` &
else
echo "process already exists..."
fi
done

Answer 1

maybe remove the space in the end of COMMAND