How to deploy python crawler scripts on Linux and set up scheduled tasks

# Download pip installation package wget "https://pypi.python.org/packages/source/p/pip/pip-1.5.4.tar.gz#md5=834b2904f92d46aaa333267fb1c922bb" --no-check-certificate
# Unzip the installation package and install tar -xzvf pip-1.5.4.tar.gz
cd pip-1.5.4
python setup.py install

pip install PyGreSQL==5.0.3
pip install requests==2.18.3

# Start the scheduled task service service crond start
# View the scheduled task service status service crond status
# Open the scheduled task editing window crontab -e 
# Add two scheduled tasks, which will be executed once at 0:00 and 12:20 every day, and written to the log 0 0 * * * /usr/bin/python /home/longrise/psrd/collect.py > /home/longrise/psrd/collect.log 2>&1 &

20 12 * * * /usr/bin/python /home/longrise/psrd/collect.py > /home/longrise/psrd/collect.log 2>&1 &

The syntax of scheduled tasks is as follows:
# For details see man 4 crontabs

# Example of job definition:
# .---------------- minute (0 - 59)
# | .------------- hour (0 - 23)
# | | .---------- day of month (1 - 31)
# | | | .------- month (1 - 12) OR jan,feb,mar,apr ...
# | | | | .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
# | | | | |
# * * * * * user-name command to be executed