shell脚本只运行一个实例

#

PID_FILE=/tmp/$0.pid

#!!!!!!!!!!!!check previous instance
if [ -e ${PID_FILE} ]
then
echo "the previous instance has exist.";
exit 0;
fi
#
echo $$ > ${PID_FILE}
trap "rm -rf ${PID_FILE}; exit 0" HUP INT QUIT FPE KILL TERM

# ----------------------put your command here ---------------------------------------

for ((i=0; i < 100; i++))
do
python recm.py \
../test/mp4 \
'http://192.168.1.252:8088'

sleep 60
done

#------------------------------------------------------------------------------------

# !!!!!!!!!!!do not remove this command
rm -rf ${PID_FILE}