Ubuntu crontab question

[csendesmark]

Hello All
I have Ubuntu 24.04.1 x64 installed on my smol rig, functioning as a NAS
Added the following commands to create a report of the HDDs for me each day:
0 5 * * * date +%Y-%m-%d >> /path/storage-state.txt;uptime >> /path/storage-state.txt;df -h|grep home >> /path/storage-state.txt;/path/HDSentinel -solid >> /path/storage-state.txt

The latest addition is the first command with the date, and if I put there, none of the commands are completing,
If I just run this line in terminal with all 4 command, no problem. Each command get executed with no issue.
But in crontab it is simply behaving like it's commented out or something, with:
0 5 * * * uptime >> /path/storage-state.txt;df -h|grep home >> /path/storage-state.txt;/path/HDSentinel -solid >> /path/storage-state.txt
There is no issue, why is date so hard for my linux?

 

[bug]

I can't see anything apparently wrong. But I would put all that in a script and just do:
0 5 * * * storage-state.sh >> /path/storage-state.txt 2>&1

That last bit is just in case. Cron doesn't have a console and if smth errs, everything goes into oblivion.

 

[csendesmark]

Alright, give this to your 90%
But I am still curious why this "simple" way failed me.

 

[t0t0]

man 5 crontab:

The "sixth" field (the rest of the line) specifies the command to be run. The entire command portion of the line, up to a newline or % character, will be executed by /bin/sh or by the shell specified in the SHELL variable of the cronfile. Percent-signs (%) in the command, unless escaped with backslash (\), will be changed into newline characters, and all data after the first % will be sent to the command as standard input.

 

[bug]

man 5 crontab:

Nice. I was suspecting syntax or the command trying to write to stderr. But I couldn't spot it.

@csendesmark That's not my 90%. I'm happy if I get things right 80% of the time, but I am well aware my average is well below that.

 

[csendesmark]

man 5 crontab:

Damn, I was totally lost on the point when I submitted the commands manually were ok.
Hindsight it is so obvious, also - I would argue on Linux has room to improve...
This one is a bit silly.

That's not my 90%

Still, I will use the script from now on, I hate when systems are handling stuff different when you expect the same.
Will not put "complex" stuff into the "simple" crontab ever again.

You can archive this

 

[Mindweaver]

I would add backslashes in the date to escape the percent signs(%). So the percent signs are interpreted correctly by the date command rather than being treated as special characters by the shell. I just saw this and haven't had my first cup of coffee.. so you got my 20% at best here. lol

Try this it has more error logging.

0 5 * * * /bin/bash -c 'date +\%Y-\%m-\%d >> /path/storage-state.txt; uptime >> /path/storage-state.txt; df -h | grep home >> /path/storage-state.txt; /path/HDSentinel -solid >> /path/storage-state.txt' 2>> /path/error.log

 

[bug]

I would add backslashes in the date to escape the percent signs(%). So the percent signs are interpreted correctly by the date command rather than being treated as special characters by the shell. I just saw this and haven't had my first cup of coffee.. so you got my 20% at best here. lol

Try this it has more error logging.

0 5 * * * /bin/bash -c 'date +\%Y-\%m-\%d >> /path/storage-state.txt; uptime >> /path/storage-state.txt; df -h | grep home >> /path/storage-state.txt; /path/HDSentinel -solid >> /path/storage-state.txt' 2>> /path/error.log

@t0t0 Already pointed that out. Still, it's good practice to put everything into a script, call that from crontab and redirect outputs as needed. Works every time.

Kudos for spotting it before the coffee though, I wasn't even aware of that crontab oddity.

 

[Mindweaver]

@t0t0 Already pointed that out. Still, it's good practice to put everything into a script, call that from crontab and redirect outputs as needed. Works every time.

Kudos for spotting it before the coffee though, I wasn't even aware of that crontab oddity.

Aww yeah good catch.. I have coffee now. lol Sorry @t0t0 ! Thanks bug! I'm starting to see color again

also, I wanted to add yes 100% agree with putting everything into a script. Plus, it makes it easier to read if you format it correctly.

 

[csendesmark]

Aww yeah good catch.. I have coffee now. lol Sorry @t0t0 ! Thanks bug! I'm starting to see color again

also, I wanted to add yes 100% agree with putting everything into a script. Plus, it makes it easier to read if you format it correctly.

Do I need the escape char in the script tho?

 

[Solaris17]

Do I need the escape char in the script tho?

That is a question that is 1000 feet deep depending on host variables and system configuration. But no in your case you don’t.

I would run the script redirect output to a log and append date to it.

 

[csendesmark]

Checked,
My system works without the escape char.

 

[Mindweaver]

Do I need the escape char in the script tho?

What @Solaris17 said. Here is how I would put the script for readability. This will put all errors in this error.log file.

0 5 * * * {
  date +%Y-%m-%d >> /path/storage-state.txt
  uptime >> /path/storage-state.txt
  df -h | grep home >> /path/storage-state.txt
  /path/HDSentinel -solid >> /path/storage-state.txt
} 2>> /path/error.log