On 2024-07-06 04:50, Andrey Repin via Cygwin wrote:
I'm trying to install a new cron job, and the thing fails claiming that it
didn't see the edits I made to the file.
# echo "USER=$USER" | crontab -
# crontab -l
# DO NOT EDIT THIS FILE - edit the master and reinstall.
# (- installed on Sat Jul 6 13:35:43 2024)
# (Cron version V5.0 -- $Id: crontab.c,v 1.12 2004/01/23 18:56:42 vixie Exp $)
USER=anrdaemon
# crontab -e
### do some edits…
crontab: no changes made to crontab
What is your editor, how is it configured, how is it invoked, and how are VISUAL
and EDITOR defined?
Most commands that use an editor for some commands effectively invoke
${VISUAL:-${EDITOR:-vi}}.
For example, I run gvim under X, it backgrounds, so I have VISUAL='gvim -f' and
EDITOR=vim so gvim stays in the foreground for crontab, git, etc. and the same
process and PID is used as forked.
For cygport, it only looks at EDITOR, so in ~/.cygwin_aliases, I have:
alias cygport="EDITOR=\"$VISUAL\" cygport"
Your editor also has to behave as if it updates the temporary filename it is
invoked with, as from:
$ mktemp --tmpdir crontab.XXXXXXXXXX
for example /tmp/crontab.??????????, save changes into that file, and leave it
changed when exiting, and other than nano's own /tmp/nano.?????? files, I see no
special handling.
The source has the following note:
https://github.com/vixie/cron/blob/master/crontab.c#L389
which assumes that editors rewrite original files rather than renaming/unlinking
because that allows security issues, so it compares the fstat mtime to the saved
value to detect changes.
Piping a new file to the crontab works, but that's "slightly" cumbersome.
What is it missing why it does not want to just work?
-- Few moments later… ---
It seems crontab dislikes safe file writes.
What do you mean by safe file writes?
$ stat x > 1; nano x; stat x > 2; diff -u0 1 2
$ stat x > 1; $EDITOR x; stat x > 2; diff -u0 1 2
What do these show?
If you are using `nano`, that should work, as it is used in almost every example
from RaspberryPi, and someone would have complained!
Unless the Cygwin package config differs from the Debian config, and it does not
appear to significantly.
Is there a way around it that does not involve replacing crontab tool with my
own script that has no such issue?
See above to fix the issue, or use:
$ $VISUAL $HOME/$USER.crontab
$ crontab $HOME/$USER.crontab
$ crontab -l
--
Take care. Thanks, Brian Inglis Calgary, Alberta, Canada
La perfection est atteinte Perfection is achieved
non pas lorsqu'il n'y a plus rien à ajouter not when there is no more to add
mais lorsqu'il n'y a plus rien à retirer but when there is no more to cut
-- Antoine de Saint-Exupéry
--
Problem reports: https://cygwin.com/problems.html
FAQ: https://cygwin.com/faq/
Documentation: https://cygwin.com/docs.html
Unsubscribe info: https://cygwin.com/ml/#unsubscribe-simple
