cron does not read $PATH

[Humphrey van Polanen Petel]

PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games

Gnome _schedule command preview=/usr/local/bin/bup && tail -f /var/mail/humphrey >~/Desktop/bup-log

/usr/local/bin contains bin

log contains
--
Content-Type: text/plain; charset=ANSI_X3.4-1968
X-Cron-Env: <SHELL=/bin/sh>
X-Cron-Env: <HOME=/home/humphrey>
X-Cron-Env: <PATH=/usr/bin:/bin>
X-Cron-Env: <LOGNAME=humphrey>
Message-Id: <20160110054001.2130AF227EB@David>
Date: Sun, 10 Jan 2016 16:40:01 +1100 (AEDT)

/bin/sh: 1: bup: not found
--

cron does not read PATH

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: cron 3.0pl1-124ubuntu2
ProcVersionSignature: Ubuntu 3.16.0-57.77~14.04.1-generic 3.16.7-ckt20
Uname: Linux 3.16.0-57-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.19
Architecture: amd64
CurrentDesktop: Unity
Date: Fri Jan 15 10:39:57 2016
InstallationDate: Installed on 2015-09-08 (128 days ago)
InstallationMedia: Ubuntu 14.04.2 LTS "Trusty Tahr" - Release amd64 (20150218.1)
SourcePackage: cron
UpgradeStatus: No upgrade log present (probably fresh install)

[Humphrey van Polanen Petel (hpvpp)]

If cron doesn't read $PATH then the only things cron recognizes is inbuilt commands.

Okay, I (now) know how to work around it, but I think it is *seriously* bad publicity for linux systems.

[Christian Kastner (ckk)]

On 2016-01-15 00:47, Humphrey van Polanen Petel wrote:
> PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games
>
> Gnome _schedule command preview=/usr/local/bin/bup
  ^^^^^^^^^^
That's not a cron command, that is some independent Gnome frontend. cron
only reads crontabs from /var/spool/cron/crontabs.

You create and edit crontabs by executing "crontab -e". For information
on how to set PATH for cron jobs, please see crontab(5). Anything else
you'll have to report against Gnome.

Regards,
Christian

[Humphrey van Polanen Petel (hpvpp)]

Dear Christian,

Just so you know, it *is* a cron command.
Gnome Schedule is nothing but a pretty gui to crontab.
I suggest you be a bit more charitable when reading bug reports.

After some study of the documentation, I have come to the conclusion that cron/crontab is very much in need of a revamp. Certainly, it does the job, but then that depends on how the job-requirements are defined. To be sure, it is probably very difficult and much more complex than I can imagine, but being used to the Windows Task Scheduler I suggest that it could be a lot more user-friendly.

[Christian Kastner (ckk)]

On 2016-01-19 04:01, Humphrey van Polanen Petel wrote:
> Just so you know, it *is* a cron command.
> Gnome Schedule is nothing but a pretty gui to crontab.

And that pretty GUI is from an entirely separate package than package
cron, against which you reported the bug.

> I suggest you be a bit more charitable when reading bug reports.

Please follow your own suggestion. I already explained how cron works:
via crontabs, ie plaintext files in a specific directory. If a client
program (be it from Gnome, KDE, or whatever) uses this interface
incorrectly, then it is up to the client program to fix this. Hence why
I said "you'll have to report it against Gnome".

If you had read crontab(5) as I suggested, then you would know that to
modify the $PATH of a job, one must specify a PATH variable in the
crontab file. You seem to expect Gnome Schedule to do this for you (when
it presumably generates a crontab), but evidently it isn't doing it.
That is clearly not a problem in cron, but in Gnome Schedule.

> After some study of the documentation, I have come to the conclusion
> that cron/crontab is very much in need of a revamp. Certainly, it does
> the job, but then that depends on how the job-requirements are defined.
> To be sure, it is probably very difficult and much more complex than I
> can imagine, but being used to the Windows Task Scheduler I suggest that
> it could be a lot more user-friendly.

I agree that the mode in which cron operates is antiquated.
Nevertheless, it is mandated by POSIX:

http://pubs.opengroup.org/onlinepubs/9699919799/utilities/crontab.html

More powerful job schedulers exist, but the intention behind cron is to
provide a simple, consistent, and ever-present interface in
POSIX-compliant environments.

Regards,
Christian

[Humphrey van Polanen Petel (hpvpp)]

okay