Running shell script in cron

Question

I am using ubuntu in rapsberry pi 2. I want my script to be ran after I login because it is a GUI program. I have tried to edit /etc/profile and it runs the program before enter the desktop so it cause some of the GUI failed to run. Therefore, I tried to use crontab and it works but I faced some problems.

Here is the line I appended into crontab.

@reboot sh /home/ubuntu/testing.sh >/home/ubuntu/logs/cronlog 2>&1

Here is my script.

#!/bin/bash
source /home/ubuntu/ros_package/devel/setup.bash
roslaunch uvc_camera camera_node.launch &
source /home/ubuntu/catkin_ws/devel/setup.bash
rosrun hybrid_tracking ir_track

Here is my output log.

/home/ubuntu/testing.sh: 3: /home/ubuntu/testing.sh: source: not found

/home/ubuntu/testing.sh: 20: /home/ubuntu/testing.sh: source: not found

/home/ubuntu/testing.sh: 4: /home/ubuntu/testing.sh:

/home/ubuntu/testing.sh: 21: /home/ubuntu/testing.sh: rosrun: not found roslaunch: not found

I have tested my script and it is running in terminal but why there are errors when I run it in cron?

• ott--: cron executes the scripts using /bin/sh, so the command source is unknown. Use a simple . ( a dot) to include scripts.

Answer 1

This might be due to access right problems.

Your crontab entry must be run with correct user to have access to the home folder of user ubuntu. So you either add the entry as user ubuntu doing running crontab, as root running crontab -u ubuntu -e, or you can put your entry into a file in /etc/cron.d with an entry formatted as a normal cronjob, but with an extra user field:

#<timing> <user> <command>
11 * * * * ubuntu /home/ubuntu/testing.sh

Furthermore make shure that your commands are accessible, probably use absolute paths.

• Sam: I have tested sudo crontab -u ubuntu -e but the result still the same. How to put entry in /etc/cron.d?
• theldoria: You should add a file without extension into that directory. Please refer to man cron(8) for more information.
• theldoria: What's much more important, however, is to use absolute pahts to roslaunch and what you else call. Find the absolute path to hem by using type, e.g. type roslaunch.
• Sam: Now it works. It ran but it failed to open the display.
• theldoria: I guess you want to start a ros node on boot, maybe using ros-system-daemon-groovy is a way to do it.

Answer 2

I actually found out the answer.

sudo nano /etc/cron.d/anacron

Append this line at the bottom.

@reboot user_name export DISPLAY=:0 && /bin/bash /home/user/testing.sh>/home/user/logs/cronlog 2>&1

My script.

sleep 10
lxterminal -e /home/user/xxx.sh

It can straight away open the script but I use one script to run another script because I need the terminal. Straight away open terminal will face error "cannot open display" in my case. Seem like it haven get ready so I delay 10 seconds and run it.