bash script running from command line but not from cron - php

Question

I have a bash program that picks data from a file and delivers these data (if fulfilling a threshold) to another file.
It is a php script inside the bash script named smaoutput-analyse.sh
When executed from the shell it functions perfect.
When executed as a cron job as root is is executed correct, but there is no output.
Here is the output from grep -i cron /var/log/syslog
Aug 14 16:06:01 raspberrypi CRON[6705]: (root) CMD (/home/pi/scripts/SBFspot.sh > /home/pi/test/smaoutput.txt 2>&1 )
Aug 14 16:06:01 raspberrypi CRON[6706]: (root) CMD (/home/pi/test/smaoutput-analyse.sh > /dev/null 2>&1)
The information is (as mentioned before) correctly added when running fom the shell
#!/usr/bin/php
<?php
echo " Programm to read smaoutput.txt",PHP_EOL;
// etc etc
`if(!file_put_contents("sma_saved_data.txt",$sma_saved_data_string,FILE_APPEND)){
// failure
echo "error opening the file sma_saved_data.txt for writing",PHP_EOL;
}
// etc etc
?>
Here are the crontab lines:
# Every minute result of SMA
*/1 8-22 * * * /home/pi/scripts/SBFspot.sh > /home/pi/test/smaoutput.txt 2>&1
# afterwards read and save in file
*/1 10-20 * * * /home/pi/test/smaoutput-analyse.sh > /dev/null 2>&1
I think I have set file permissions correct +rw for the files and +rwx for the bash
What did I miss

Answer 1

You should check the following issues:
Are all the environment variables the same? So call printenv from bash and create a cron-job */1 8-22 * * * printenv > /tmp/printenv.txt --> Compare the ouput of file /tmp/printenv.txt with printenv from bash
Are you executing with the same user and the same permissions? Execute echo "$USER" and create a cron-job */1 8-22 * * * echo "$USER" > /tmp/user.txt --> Compare the ouput of file /tmp/user.txt with echo "$USER" from bash
Check the path you executing the script. Call pwd from bash and create a cron-job */1 8-22 * * * pwd> /tmp/pwd.txt --> Compare the ouput of file /tmp/pwd.txt with the ouput of pwd from bash

Answer 2

Realy interesting.
This was my first post and I received quite a swift response.
Thank you!
The solution was simple: provide the full path to where you want to keep the file.
Remark: To be shure that everything will be executed I alway put cronjobs in a root crontab and not in a user crontab.
Maybe that is "smart thinking" but not so smart acting.
I would appreciate to get some comment on this root cronjob idea.
The post about executing printenv, echo "&USER" and pwd both from bash and from cron was interesting.
The printenv from bash gives a lot of information, amongs which SHELL=/bin/bash, SSH_CLIENT, SSH_TTY. MAIL, PATH, SSH_CONNECTION and lots more starting with LS_COLORS, the printenv from cron is just 6 lines HOME=/root, LOGNAME=root, PATH=/usr/bin, LANG=en_GB,UTF-8, SHELL=/bin/sh and PWD=/root
The echo "&USER" from bash gives pi, whilst from cron gives a blank file
The pwd from bash gives /home/pi/test and from cron /root
These results are understandable.
Can I learn from it that I should create cronjobs as user pi and not as user root?