Bash script not working in crontab

Question

I'm trying to make a Bash-script which checks if I've downloaded anything, and if I have it should scan that. I'm making it launch at startup using crontab, however that part doesn't work.

This is my code:

#!/bin/bash

inotifywait ~/Downloads -m -r -e modify -e moved_to --format '%w%f' | while read file
do
    $(clamscan --bell --recursive --max-filesize=99999 --log log/myLogs.txt $file)
    CLAMSCAN="$?"

    if [ $CLAMSCAN -eq 1 ]; then
        $(xmessage -buttons Ok:0,"Remove":1,"View Logs":2 -default Ok -center "Infected file: $file is found...")
        CHOICE="$?"

        if [ $CHOICE -eq 1 ]; then
            $(rm -r $file)
        elif [ $CHOICE -eq 2 ]; then
            $(xmessage -buttons Ok:0 -default Ok -center -file log/myLogs.txt)
        fi      
    fi
done

My crontab:

# Edit this file to introduce tasks to be run by cron.
# 
# Each task to run has to be defined through a single line
# indicating with different fields when the task will be run
# and what command to run for the task
# 
# To define the time you can provide concrete values for
# minute (m), hour (h), day of month (dom), month (mon),
# and day of week (dow) or use '*' in these fields (for 'any').# 
# Notice that tasks will be started based on the cron's system
# daemon's notion of time and timezones.
# 
# Output of the crontab jobs (including errors) is sent through
# email to the user the crontab file belongs to (unless redirected).
# 
# For example, you can run a backup of all your user accounts
# at 5 a.m every week with:
# 0 5 * * 1 tar -zcf /var/backups/home.tgz /home/
# 
# For more information see the manual pages of crontab(5) and cron(8)
# 
# m h  dom mon dow   command
SHELL=/bin/sh
@reboot sh $HOME/.custom_security/Downloads_sec.sh

When I change directory to e.g '/', and then run sh $HOME/.custom_security/Downloads_sec.sh I get this error:

    Setting up watches.  Beware: since -r was given, this may take a while!
Watches established.
ERROR: Can't open log/myLogs.txt in append mode (check permissions!).
ERROR: Problem with internal logger.

The script works fine as standalone script!

Answer 1

The problem is with this line:

clamscan --bell --recursive --max-filesize=99999 --log log/myLogs.txt $file

This tries to write to log/myLogs.txt. If you are in your home directory /home/oneill, it will try to write to /home/oneill/log/myLogs.txt, which is probably the correct place. If you are in the root / directory, it will try to write to /log/myLogs.txt, which it does not have the proper permissions for.

Either use absolute paths, or put a cd /home/oneill somewhere in the beginning of the script.