Executing background jobs - Permissible or not ?

[academics17]

I need to run a PhP job in the background. This will collect data and populate a mysql database. When I am doing the same on my desktop machine, I have the luxury of "kill"ing it if it misbehaves but I am not sure whether on x10 -- without shell access -- I could do the same. Again, I do not want to create a runaway program that causes difficulty to others.

What would be a good way to strategy for this requirement within the constraints of a free x10 account.

[misson]

You can have non-interactive processes that run as cron jobs. However, the high resource usage (HRU) restriction will still apply. If you're worried about a runaway PHP script, you can use set_time_limit. More generally, you can force a command to exit with:

#!/bin/bash

timeout=30
if [ $# -gt 0 ]; then
    timeout=$1
fi

/path/to/binary arg0 arg1 ... argN >$HOME/log/job.log 2>&1 &
sleep $timeout && kill $! 2>/dev/null

Replace the "/path/to/binary ... argN" with the command to run, save it as a file in ~/bin and set the cron job command to the file.

Even more generally, you can use the following script (saved as e.g. "~/bin/timelimit") to run an arbitrary command for a limited length of time. Make sure you escape any shell metacharacters when calling the script so they don't get interpreted before timelimit gets a chance to execute the command.

#!/bin/bash

timeout=30
if [ $1 -ne 0 2>/dev/null ] ; then
    timeout=$1
    shift
fi
eval "$*" &
sleep $timeout && kill $! 2>/dev/null

Example usage:

$HOME/bin/timelimit 60 cut -f 1 -d ' ' $HOME/data/activity \| sort -n \| uniq -c \>$HOME/logs/visit_counts
#or:
$HOME/bin/timelimit 60 "cut -f 1 -d ' ' $HOME/data/activity | sort -n | uniq -c >$HOME/logs/visit_counts"

For an example of how you can run multiple, specific commands with a timeout for all, read Alarms, Timeouts and Parallel Processes in Bash

[qchimex1]

academics17 : did you find out how to do this? I have same requirement of running a PHP process in background continuously ( till its killed).

[misson]

@qchimex1: you need to pay closer attention when reading, both to my post and the terms of service which you agreed to when you signed up. Both already address your post.