"tcsetattr(): Inappropriate ioctl for device" (redirection to /dev/null)

[Adam Funk]

On 2015-04-07, Nils Kassube wrote:

> Adam Funk wrote:
>> I have a cron job to run a bash script that includes the following
>> line:
>> 
>> hpodder  >/dev/null
>> 
>> Note that I'm not redirecting stderr.  Whenever the hpodder command
>> gives an error message, the cron job output also includes
>> "tcsetattr(): Inappropriate ioctl for device".  I've googled this
>> message & it usually seems related to redirecting output when changing
>> ownership/permissions, e.g., with su -c or sudo.  In my case, the
>> crontab is running in the 'adam' account, & the bash script is owned
>> by 'adam' too.
>
> The tcsetattr function is usually used for some sort of terminal device. 
> Maybe that script wants to change the terminal settings of /dev/null 
> which wouldn't make sense. What happens if you try the command from the 
> command line instead of the cron job? Do you also get the error message? 
> And what is the purpose of the script?

It runs hpodder, which is an obsolete command-line podcast-fetching
program (I've been looking for a replacement, but I couldn't get
podget to work) properly.  The cron job runs it in the morning before
I get to the office.

The strange thing is that one of my hard drives died recently (the /
one, not the /home one) so I had to reinstall the OS (and the obsolete
deb for hpodder), but I didn't need to change the script or the
hpodder database (which were still intact in my home directory).  This
ioctl warning has only appeared since the reinstallation.