Saving cron job using Putty

To show crontabs
crontab -l

To edit crontabs
crontab -e
If you do not edit it then CTRL Z will let you exit.

Then press ‘o’ to insert then add your crontab
5 1 * * * usr/bin/php /tmp/backup/senddata.php >/dev/null

Then press
'escape' to exit editor
':wq' and press enter to save and quit