CRON : Scheduling task

Question

I am using ubuntu 12.04.I am using a script(./home/sam/code/imageUpdate) to synchronising images from server to a particular folder in local system. And I have to run the script in the evening always. So I want to write a crontab which will automatically runs the script.

My commands :

$crontab -e;

And added the scheduled time to the crontab file.

# 50 17 * * * cd /home/sam
# 52 17 * * * ./code/imageUpdate > image1.txt

Then I saved the file and waited for the result.

But I didn't get any result. No image was been synchronised to image1.txt file.

Have I left any step ?

Please help me out... Thanks in advance.

Answer 1

Make sure you don't have hashes (comments) at the start of your crontab commands.

Additionally:
Crontab commands should be run in isolation.
Each crontab command will be run in its own context, changing directory in one instruction probably won't lead to that directory being sound for the next executed (they may be run in their own environments, e.g.).

To overcome this, write a simple shell script which encompasses all of your commands for a single action.

# MyCommand.sh
cd /home/sam
./code/imageUpdate > image1.txt

# crontab command
50 17 * * * /home/sam/MyCommand.sh