一開始nagios執行監控腳本的時候，總是不定期地偶爾地出現下面的錯誤
[: too many arguments
腳本一開始是這麼寫的：
guard_info=`ps aux | grep guard | grep -v grep | grep guard_replica_id | awk '{print $2}'`
echo guard_info:$guard_info
if [ "$guard_info" = "" ]; then
echo "guard is not found"
exit 0
fi
vsz=`echo $guard_info | awk '{print $3}'`
echo vsz:$vsz
cpu=`echo $guard_info | awk '{print $4}' | awk -F"." '{print $1}'`
echo cpu:$cpu
if [ $vsz -gt 606192 ]; then
echo "vsz as large as $vsz"
exit 2
elif [ $cpu -gt 5 ]; then
echo "cpu percentage is $p_cpu"
exit 2
else
exit 0
fi
最後發現是guard本身會fork子進程，在調用execve之前和fork()之後有那麼一個小時間窗口，這個時候會存在兩個相同名字相同參數的進程存在。
解決辦法就是用elapsed time來對grep出來的guard進程進行排序，取時間最長的那個。最後腳本變成這樣：
guard_info=`ps -C guard -o pid=,etime=,vsz=,%cpu= --sort -etime | head -1`
echo guard_info:$guard_info
if [ "$guard_info" = "" ]; then
echo "guard is not found"
exit 0
fi
vsz=`echo $guard_info | awk '{print $3}'`
echo vsz:$vsz
cpu=`echo $guard_info | awk '{print $4}' | awk -F"." '{print $1}'`
echo cpu:$cpu
if [ $vsz -gt 606192 ]; then
echo "vsz as large as $vsz"
exit 2
elif [ $cpu -gt 5 ]; then
echo "cpu percentage is $p_cpu"
exit 2
else
exit 0
fi