When I execute cron I get this fault
cron: can't open or create /var/run/crond.pid: Permission denied
So, how to do it without cron?
P.S. I want to check if file in svn has changed and I have a special script for it.
3 Answers
To access your personal cron configuration you should use the command crontab -e (to edit your cron table).
Alternative is the watch command:
watch -n10 command args
Finally, to monitor filesystem events more effectively, you could use inotifywait, from inotify-tools package.
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2It's worth noting, perhaps, you would better wrap your command(s) inside double quotes or you may end up with unexpected results.
watch -n<timeout> "command(s) arg(s)"likewatch -n2 "ps ux | grep ss5"– AchillesNov 10, 2018 at 10:58 -
I found it hard to get
watchto accept long, complicated commands using pipes and quotes. The while loop below worked, but of course one should always sleep first to avoid runaway pids.– rjurneyApr 25, 2019 at 23:48 -
@rjurney: it should be enough to wrap the whole command in quotes, single or better double:
watch -n10 "ls -l | grep $foo"– enzotibApr 26, 2019 at 6:15 -
@enzotib The problem comes when there are quotes in the commands, as quotes within quotes within (god help me) quotes approaches impossible in bash. In theory it should be possible but I rarely achieve nested quotes in bash without giving up and going a different route.– rjurneyApr 28, 2019 at 2:08
You can write a shell script that has sleep in a while loop.
#!/bin/sh
while [ true ]
do
sh special_svn_script.sh
sleep 10
done
answered Nov 25, 2011 at 18:31
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5
while truedoes not require square brakets, otherwise "true" is interpreted as a string, and every string is as good as "true".– enzotibNov 25, 2011 at 19:16 -
1
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1While this works you should always sleep first because something may occur causing the sleep step not to be reached, in which case you've got a runaway pid flooding something.– rjurneyApr 25, 2019 at 23:49
gnome-schedule (click the button to Install now! using your Software Center)
is a graphical user interface that leverages the power of vixie-cron, dcron and at to manage your crontab file and provide an easy way to schedule tasks on your computer. It supports recurrent (periodical) tasks and tasks that happen only once in the future. It is written in Python using pygtk.
Awesome features
- Supports custom titles and icons for your tasks so that they are more easily to keep track of
- Templates support so that you won't have to create the same task again and again; these are saved in gconf and may easily ship them with, say, a Linux distribution
- If run as root, you can edit any user's crontab and "at" tasks.
- Human-readable strings like "Every hour" instead of "0 * * * *"
- Advanced mode for crontab experts
- Provides a "panel applet" where you can manage tasks from a dropdown menu
- Predefined common expressions like: every minute, every week, tomorrow, next week A calendar allows you to choose the day you want a task executed
sudo.crontab -eto start the editor. To list the current crons, runcrontab -l