I try to run a specified command on a desired time. I found at for this, and it seems to work fine if I run:

echo "ls -al / > /home/florin/test.txt" | at 4:21am

But I want to run a different thing: /usr/bin/firefox -new-tab http://google.ro

I tried adapting the first line with my action (running it in terminal opens a new Firefox tab with http://google.ro, so the command is correct), but with at, it does not work:

echo "firefox -new-tab http://google.ro" | at 4:23am

The task seems to be scheduled, but it does not run. When running the previous line I get the default reply from at:

warning: commands will be executed using /bin/sh

Should my Firefox command be differently run in sh? Is there a way to do my action with at, or some other way? Thanks a lot!