cronでpython実行

備忘録。

####環境
Ubuntu Server 18.04.3 LTS
####コマンド
#####起動してるか確認

$ sudo /etc/init.d/cron status

#####起動

$ sudo /etc/init.d/cron start

#####停止

$ sudo /etc/init.d/cron stop

#####再起動

$ sudo /etc/init.d/cron restart

#####cronの設定
何もせず保存して終了

$ crontab -e

#####編集用ファイルの作成

$ crontab -l > .crontab.txt

#####pythonのパスを調べる

$ which python3
/usr/bin/python3

#####実行したいファイルのパスを調べる

$ readlink -f test.py
/home/houtarou/test.py

#####編集用ファイルの最後に、実行したいcronを書き書き

*/1 * * * * （pythonのパス） （実行したファイルのパス）
（例）*/1 * * * * /usr/bin/python3 /home/houtarou/test.py

を追加。

$ vim .crontab.txt

# Edit this file to introduce tasks to be run by cron.
#
# Each task to run has to be defined through a single line
# indicating with different fields when the task will be run
# and what command to run for the task
#
# To define the time you can provide concrete values for
# minute (m), hour (h), day of month (dom), month (mon),
# and day of week (dow) or use '*' in these fields (for 'any').#
# Notice that tasks will be started based on the cron's system
# daemon's notion of time and timezones.
#
# Output of the crontab jobs (including errors) is sent through
# email to the user the crontab file belongs to (unless redirected).
#
# For example, you can run a backup of all your user accounts
# at 5 a.m every week with:
# 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/
#
# For more information see the manual pages of crontab(5) and cron(8)
#
# m h  dom mon dow   command

*/1 * * * * /usr/bin/python3 /home/houtarou/test.py

#####crontabにファイルを読み込ませる

$ crontab .crontab.txt

#####crontabに反映されたか確認

$ crontab -l
# Edit this file to introduce tasks to be run by cron.
#
# Each task to run has to be defined through a single line
# indicating with different fields when the task will be run
# and what command to run for the task
#
# To define the time you can provide concrete values for
# minute (m), hour (h), day of month (dom), month (mon),
# and day of week (dow) or use '*' in these fields (for 'any').#
# Notice that tasks will be started based on the cron's system
# daemon's notion of time and timezones.
#
# Output of the crontab jobs (including errors) is sent through
# email to the user the crontab file belongs to (unless redirected).
#
# For example, you can run a backup of all your user accounts
# at 5 a.m every week with:
# 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/
#
# For more information see the manual pages of crontab(5) and cron(8)
#
# m h  dom mon dow   command

*/1 * * * * /usr/bin/python3 /home/houtarou/test.py

時間などの詳しい説明は以下を参照
https://qiita.com/katsukii/items/d5f90a6e4592d1414f99

以上