Most of the time, it's because cron jobs are using a different environment (i.e PATH and other variables) than you'd expect. What I sometimes do is to put a "sc

Most of the time, it's because cron jobs are using a different environment (i.e PATH and other variables) than you'd expect. What I sometimes do is to put a "screen -dm" command to run from cron (e.g. if you set it to run each minute and then remove it once it's run). Then, connect to the screen session and you can examine and test what's going on with the environment.