crontab jobs don't execute

[joefred]

I have been trying to create automated scripts for backing up my desktop system and my /Home/user/Documents.
System:
Linux mintJF 4.15.0-43-generic #46-Ubuntu SMP x86_64 GNU/Linux
Cinnamon Desktop

The scripts work when run from the terminal but not when scheduled with crontab -e
Script 1:
#!/bin/bash
sudo tar -cvzpf $Backup_Destination/$Backup_Snapshot_file_name-$Backup_file_timestamp.tar.gz --exclude=/dev --exclude=/run --exclude=/media --exclude=/home --exclude=/proc --exclude=/lost+found --exclude=/sys --exclude=/var --exclude=/tmp -g $Snapshots_Destination/$Backup_Snapshot_file_name-$Snapshot_file_timestamp.snap $Data_to_be_Backed_up

Roots crontab job:

0 0 * * * /bin/bash /home/myuser/Full_Backup_Systems_V1.sh

This worked from root crontab but not when placed in my user crontab.

log:
CRON[20176]: pam_unix(cron:session): session opened for user root by (uid=0)
CRON[20177]: (root) CMD (/bin/bash /home/myuser/scripts/Full_Backup_Systems_V1.sh)

Success, I think. But...

Script 2:
#!/bin/bash
sudo tar -cvzpf $Backup_Destination/$Backup_Snapshot_file_name-$Backup_file_timestamp.tar.gz -g $Snapshots_Destination/$Backup_Snapshot_file_name-$Snapshot_file_timestamp.snap $Data_to_be_Backed_up

**I know its the same script but variables are adjusted**

my user crontab jobs:

0 0 * * * /bin/bash /home/myuser/Full_Backup_Systems_V1.sh

5 20 * * 0 /bin/bash /home/myuser/myuser_Documents_Backup.sh

log:
CRON[28641]: (myuser) CMD (/bin/bash /home/myuser/myuser_Documents_Backup.sh)
CRON[28640]: (CRON) info (No MTA installed, discarding output)
CRON[28640]: pam_unix(cron:session): session closed for user myuser

I added MAILTO=""
ran it through Cron again and next log reads:

CRON[30345]: pam_unix(cron:session): session opened for user myuesr by (uid=0)
CRON[30348]: (myuser) CMD (/bin/bash /home/myuser/myuser_Documents_Backup.sh) CRON[30345]: pam_unix(cron:session): session closed for user myuser

Neither executed with myuser crontab. No further explanation.
I also tried to run Script 2 in root crontab and it failed.
There is clearly an error (permissions, env, sh) but nothing I'm finding online seems to work or I'm not understanding.

Please advise

[WharfRat]

Remove /bin/bash so it's just /home/myuser/Full_Backup_Systems_V1.sh

Is the script executable

[rene]

The scripts work when run from the terminal but not when scheduled with crontab -e

So I take it you have setup sudo to not require someone/thing entering a password when invoking tar?

In any case please note there's no need to keep guessing at output: simply install an MTA. Please see viewtopic.php?f=213&t=279203&hilit=postfix#p1537513 for that part.

[joefred]

I removed /bin/bash from the crontab job

no change. Log shows cron open job then close.

Yes. The scripts are executable.

I added MTA as suggested by rene.

mail message:

/bin/sh: 1: /home/myuser/myuser_Documents_Backup.sh: not found

Does this mean cron cannot find the script?
OR is it looking for sh instead of bash?
What does the 1 indicate?
No clear answer on google search.

Also, I edited the /etc/sudoers.d file to allow myuser to execute tar without a password.

Still doesn't run.

[WharfRat]

It can't find /home/myuser/myuser_Documents_Backup.sh

Are you sure of the name ls -lh /home/myuser/myuser_Documents_Backup.sh

[joefred]

OK. I am an idiot. The path lacked my subdirectory "scripts".
/home/myuser/scripts/myuser_Documents_Backup.sh

Now it is finding the script. However, it will not run. Here is the log message:

CRON[19341]: pam_unix(cron:session): session opened for user myuser by (uid=0)
CRON[19342]: (myuser) CMD (/home/myuser/scripts/myuser_Documents_Backup.sh )
sudo[19346]: pam_unix(sudo:auth): conversation failed
sudo[19346]: pam_unix(sudo:auth): auth could not identify password for [myuser]
CRON[19341]: pam_unix(cron:session): session closed for user myuser

The script does start but seems to hang on the command 'sudo tar'
because this is the message in my mail:

This Script backs up myuser's Documents. [Om

sudo: no tty present and no askpass program specified
?

Well, now I have a new problem. Apparently I messed up the sudoers file and can no longer su ...uh oh.

[WharfRat]

If you have to have escalated privileges then use root's crontab or /etc/crontab.

It's failing because it can't get your sudo password to allow the escalated privileges.

[ajgringo619]

Also, I edited the /etc/sudoers.d file to allow myuser to execute tar without a password.
Still doesn't run.

Did you use visudo to edit the file (you did mean /etc/sudoers, right?)? Can you post - I believe you need to use the full path to the program in question, something like this:

Code: Select all

me 	ALL=(ALL:ALL) NOPASSWD: /usr/bin/timeshift --list

[joefred]

Yes. I used this:
sudo visudo
myuser ALL=(ALL) NOPASSWD: /bin/tar

I've changed to using root's crontab. Everything works fine that way.