Hardware Reference
In-Depth Information
Scheduling regular updates
While we've done plenty of command scheduling with
at
in this topic, it will only
run a command once. If we need a command to be run regularly at certain times,
cron
is better for the job and is already installed. To add a new task to run, we need
to add it to our scheduling table, or
crontab
, with the following command:
pi@raspberrypi ~ $ crontab -e
Add your task to the bottom of the file on a blank line according to the following form:
Minute | Hour | Day of month | Month | Day of week | Command to
execute
For example, to tweet a status update every hour:
0 * * * * ttytter -status="Alive: $(date)"
To tweet a status update every 10 minutes:
*/10 * * * * ttytter -status="Alive: $(date)"
You can also use one of the special predefined values among
@hourly
,
@daily
,
@weekly
,
@monthly
,
@yearly
, or
@reboot
to have a command run at startup.
Once you're happy with your line, save and exit
nano
to have your new
crontab
installed. To view your
crontab
, use this command:
pi@raspberrypi ~ $ crontab -l
Accessing your files from anywhere with
Dropbox
Dropbox is a popular file hosting service with client software available for a wide
range of devices. In essence, Dropbox allows you to store files in a special folder
on one computer and have the files appear automatically on any other device with
Dropbox installed. Files may also be accessed and modified through a regular
web browser.
Unfortunately, the company behind Dropbox does not yet offer client software for
the Raspberry Pi. Instead we'll be using a bash script called Dropbox Uploader that
works just as well, and is in some ways even more flexible than the native client.
