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I have a script that checks if the PPTP VPN is running, and if not it reconnects the PPTP VPN. When I run the script manually it executes fine, but when I make a cron job, it's not running.
* * * * * /bin/bash /var/scripts/vpn-check.sh
Here is the script:
#!/bin/sh
/bin/ping -c3 192.168.17.27 > /tmp/pingreport
result=`grep "0 received" /tmp/pingreport`
truncresult="`echo "$result" | sed 's/^\(.................................\).*$$'`"
if [[ $truncresult == "3 packets transmitted, 0 received" ]]; then
/usr/sbin/pppd call home
fi
finally i found a solution ... instead of entering the cronjob with
crontab -e
i needed to edit the crontab file directly
nano /etc/crontab
adding e.g. something like
*/5 * * * * root /bin/bash /var/scripts/vpn-check.sh
and its fine now!
Thank you all for your help ... hope my solution will help other people as well.
After a long time getting errors, I just did this:
SHELL=/bin/bash
PATH=/bin:/sbin:/usr/bin:/usr/sbin
* * * * * /bin/bash /home/joaovitordeon/Documentos/test.sh
Where test.sh contains:
#!/bin/bash
/usr/bin/python3 /home/joaovitordeon/Documentos/test.py;
In my case, the issue was that the script wasn't marked as executable. To make sure it is, run the following command:
chmod +x your_script.sh
If you're positive the script runs outside of cron, execute
printf "SHELL=$SHELL\nPATH=$PATH\n* * * * * /bin/bash /var/scripts/vpn-check.sh\n"
Do crontab -e for whichever crontab you're using and replace it with output of the above command. This should mirror most of your environment in case there is some missing path issue or something else. Also check logs for any errors it's getting.
Though it definitly looks like the script has an error or you messed something up when copying it here
sed: -e expression #1, char 44: unterminated `s' command
./bad.sh: 5: ./bad.sh: [[: not found
Simple alternate script
#!/bin/bash
if [[ $(ping -c3 192.168.17.27) == *"0 received"* ]]; then
/usr/sbin/pppd call home
fi
Your script can be corrected and simplified like this:
#!/bin/sh
log=/tmp/vpn-check.log
{ date; ping -c3 192.168.17.27; } > $log
if grep -q '0 received' $log; then
/usr/sbin/pppd call home >>$log 2>&1
fi
Through our discussion in comments we confirmed that the script itself works, but pppd doesn't, when running from cron. This is because something must be different in an interactive shell like your terminal window, and in cron. This kind of problem is very common by the way.
The first thing to do is try to remember what configuration is necessary for pppd. I don't use it so I don't know. Maybe you need to set some environment variables? In which case most probably you set something in a startup file, like .bashrc, which is usually not used in a non-interactive shell, and would explain why pppd doesn't work.
The second thing is to check the logs of pppd. If you cannot find the logs easily, look into its man page, and it's configuration files, and try to find the logs, or how to make it log. Based on the logs, you should be able to find what is missing when running in cron, and resolve your problem.
Was having a similar problem that was resolved when a sh was put before the command in crontab
This did not work :
#reboot ~myhome/mycommand >/tmp/logfile 2>&1
This did :
#reboot sh ~myhome/mycommand >/tmp/logfile 2>&1
my case:
crontab -e
then adding the line:
* * * * * ( cd /directory/of/script/ && /bin/sh /directory/of/script/scriptItself.sh )
in fact, if I added "root" as per the user, it thought "root" was a command, and it didn't work.
As a complement of other's answers, didn't you forget the username in your crontab script ?
Try this :
* * * * * root /bin/bash /var/scripts/vpn-check.sh
EDIT
Here is a patch of your code
#!/bin/sh
/bin/ping -c3 192.168.17.27 > /tmp/pingreport
result=`grep "0 received" /tmp/pingreport`
truncresult=`echo "$result" | /bin/sed 's/^\(.................................\).*$/\1/'`
if [[ $truncresult == "3 packets transmitted, 0 received" ]]; then
/usr/sbin/pppd call home
fi
In my case, it could be solved by using this:
* * * * * root ( cd /directory/of/script/ && /directory/of/script/scriptItself.sh )
I used some ./folder/-references in the script, which didn't work.
The problem statement is script is getting executed when run manually in the shell but when run through cron, it gives "java: command not found" error -
Please try below 2 options and it should fix the issue -
Ensure the script is executable .If it's not, execute below -
chmod a+x your_script_name.sh
The cron job doesn’t run with the same user with which you are executing the script manually - so it doesn't have access to the same $PATH variable as your user which means it can't locate the Java executable to execute the commands in the script. We should first fetch the value of PATH variable as below and then set it(export) in the script -
echo $PATH can be used to fetch the value of PATH variable.
and your script can be modified as below - Please see second line starting with export
#!/bin/sh
export PATH=<provide the value of echo $PATH>
/bin/ping -c3 192.168.17.27 > /tmp/pingreport
result=`grep "0 received" /tmp/pingreport`
truncresult="`echo "$result" | sed 's/^\(.................................\).*$$'`"
if [[ $truncresult == "3 packets transmitted, 0 received" ]]; then
/usr/sbin/pppd call home
fi
First of all, check if cron service is running. You know the first question of the IT helpdesk: "Is the PC plugged in?".
For me, this was happening because the cronjob was executing from /root directory but my shell script (a script to pull the latest code from GitHub and run the tests) were in a different directory. So, I had to edit my script to have a cd to my scripts folder. My debug steps were
Verified that my script run independent of cron job
Checked /var/log/cron to see if the cron jobs are running. Verified that the job is running at the intended time
Added an echo command to the script to log the start and end times to a file. Verified that those were getting logged but not the actual commands
Logged the result of pwd to the same file and saw that the commands were getting executed from /root
Tried adding a cd to my script directory as the first line in the script. When the cron job kicked off this time, the script got executed just like in step 1.
it was timezone in my case. I scheduled cron with my local time but server has different timezone and it does not run at all. so make sure your server has same time by date cmd
first run command env > env.tmp
then run cat env.tmp
copy PATH=.................. Full line and paste into crontab -e, line before your cronjobs.
try this
/home/your site folder name/public_html/gistfile1.sh
set cron path like above
on my raspberry pi (raspbian running) I would like to have the current desktop switched to desktop n#0 after 5 minutes of idle system (no mouse or keyboard action), through wmctrl -s 0 and xprintidle for idle time checking.
Please keep in mind I'm no expert...
I tried 2 different ways, none of them working and I was wondering which one of them is the best way to do have the job done:
bash script and crontab
I wrote a simple script which checks if xprintidle is greater than a previously set $IDLE_TIME, than it switches desktops (saved in /usr/local/bin/switchDesktop0OnIdle):
#!/bin/bash
# 5 minutes in ms
IDLE_TIME=$((5*60*1000))
# Sequence to execute when timeout triggers.
trigger_cmd() {
wmctrl -s 0
}
sleep_time=$IDLE_TIME
triggered=false
while sleep $(((sleep_time+999)/1000)); do
idle=$(xprintidle)
if [ $idle -ge $IDLE_TIME ]; then
if ! $triggered; then
trigger_cmd
triggered=true
sleep_time=$IDLE_TIME
fi
else
triggered=false
# Give 100 ms buffer to avoid frantic loops shortly before triggers.
sleep_time=$((IDLE_TIME-idle+100))
fi
done
script itself works.
Then I added it to crontab (crontab -e) for have it run every 6 minutes
*/6 * * * * * sudo /usr/local/bin/switchDesktop0OnIdle
not sure sudo is necessary or not.
Anyway It doesn't work: googling around I understood that crontab runs in its own environment with its own variables. Even though I don't remember how to access this environment (oops) I do remember that I get these 2 errors running the script in it (which correctly works in "normal" shell)
could not open display (is it important ?)
bla bla -ge error, unary operator expected or similar: basically xprintidle doesn't work in this environment a gives back an empty value
What am I missing ?
infinite-while bash script running as daemon
second method I tried to set up a script with an internal infinite-while checking if xprintidle is greater then 5 minutes. In this case desktop is switched (less elegant?). Saved also in /usr/local/bin/switchDesktop0OnIdle
#!/bin/bash
triggered=false
while :
do
if [ `xprintidle` -ge 300000 ]; then
if [ triggered == false ]
wmctrl -s 0
triggered = true
fi
else
triggered = false
fi
fi
done
again the script itself works.
I tried to create a daemon in /etc/init.d/switchDesktop0OnIdle (really not an expert here, modified an existing one)
#! /bin/sh
# /etc/init.d/switchDesktop0OnIdle
### BEGIN INIT INFO
# Provides: switchDesktop0OnIdle
# Required-Start: $all
# Required-Stop: $all
# Should-Start:
# Should-Stop:
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description:
# Description:
### END INIT INFO
DAEMON=/usr/local/bin/switchDesktop0OnIdle
NAME=switchDesktop0OnIdle
test -x $DAEMON || exit 0
case "$1" in
start)
echo -n "Starting daemon: "
start-stop-daemon --start --exec $DAEMON
echo "switchDesktop0OnIdle."
;;
stop)
echo -n "Shutting down daemon:"
start-stop-daemon --stop --oknodo --retry 30 --exec $DAEMON
echo "switchDesktop0OnIdle."
;;
restart)
echo -n "Restarting daemon: "
start-stop-daemon --stop --oknodo --retry 30 --exec $DAEMON
start-stop-daemon --start --exec $DAEMON
echo "switchDesktop0OnIdle."
;;
*)
echo "Usage: $0 {start|stop|restart}"
exit 1
esac
exit 0
I set it up
sudo update-rc.d switchDesktop0OnIdle defaults
and
sudo service switchDesktop0OnIdle start
(necessary?)
...and nothing happens...
also I don't find the process with ps -ef | grep switchDesktop0OnIdle but it seems running with sudo service switchDesktop0OnIdle status
can anyone please help?
thank you
Giuseppe
As you suspected, the issue is that when you run your scripts from init or from cron, they are not running within the GUI environment you want them to control. In principle, a Linux system can have multiple X environments running. When you are using one, there are environment variables that direct the executables you are using to the environment you are in.
There are two parts to the solution: your scripts have to know which environment they are acting on, and they have to have authorization to interact with that environment.
You almost certainly are using a DISPLAY value of ":0", so export DISPLAY=:0 at the beginning of your script will handle the first part of the problem. (It might be ":0.0", which is effectively equivalent).
Authorization is a bit more complex. X can be set up to do authorization in different ways, but the most common is to have a file .Xauthority in your home directory which contains a token that is checked by the X server. If you install a script in your own crontab, it will run under your own user id (you probabl shouldn't use sudo), so it will read the right .Xauthority file. If you run from the root crontab, or from an init script, it will run as the root user, so it will have access to everything but will still need to know where to take the token from. I think that adding export XAUTHORITY=/home/joe/.Xauthority to the script will work. (Assuming your user id is joe.)
I have this script:
#!/bin/sh
while [ true ] ; do
urlfile=$( ls /root/wget/wget-download-link.txt | head -n 1 )
dir=$( cat /root/wget/wget-dir.txt )
if [ "$urlfile" = "" ] ; then
sleep 30
continue
fi
url=$( head -n 1 $urlfile )
if [ "$url" = "" ] ; then
mv $urlfile $urlfile.invalid
continue
fi
mv $urlfile $urlfile.busy
wget -b $url -P $dir -o /www/wget.log -c -t 100 -nc
mv $urlfile.busy $urlfile.done
done
The script basically checks for any new URLs at wget-download-link.txt for every 30 seconds and if there's a new URL it'll download it with wget, the problem is that when I try to run this script on Putty like this
/root/wget/wget_download.sh --daemon
it's still running in the foreground, I still can see the terminal output. How do I make it run in the background ?
In OpenWRT there is neither nohup nor screen available by default, so a solution with only builtin commands would be to start a subshell with brackets and put that one in the background with &:
(/root/wget/wget_download.sh >/dev/null 2>&1 )&
you can test this structure easily on your desktop for example with
(notify-send one && sleep 15 && notify-send two)&
... and then close your console before those 15 seconds are over, you will see the commands in the brackets continue execution after closing the console.
The following command will also work:
((/root/wget/wget_download.sh)&)&
This way you don't have to install the 'nohub' command in the tight memory space of the router used for OpenWrt.
I found this somewhere several years ago. It works.
The &at the end of script should be enough, if you see output from the script it means, that stdout and/or stderr is not closed, or not redirect to /dev/null
You can use this answer:
How to redirect all output to /dev/null
I am using openwrt merlin and the only way to get it working was using the crud cron manager[1]. Nohub and screen are not available as solutions.
cru a pinggw "0 * * * * /bin/ping -c 10 -q 192.168.2.254"
works like charm
[1][https://www.cyberciti.biz/faq/how-to-add-cron-job-on-asuswrt-merlin-wifi-router/]
https://openwrt.org/packages/pkgdata/coreutils-nohup
opkg update
opkg install coreutils-nohup
nohup yourscript.sh &
You can use nohup.
nohup yourscript.sh
or
nohup yourscript.sh &
Your script will keep running even if you close your putty session, and all the output will be written to a text file in same directory.
nohup is often used in combination with the nice command to run processes on a lower priority.
nohup nice yourscript.sh &
See: http://en.wikipedia.org/wiki/Nohup
For busybox in Openwrt Merlin system, I got a better solution which combined cru and date command
cru a YOUR_UNIQUE_CRON_NAME "`date -D '%s' +'%M %H %d %m *' -d $(( \`date +%s\`+2*60 ))` YOUR_CMD_HERE"
which add a cron job running 2 minutes later, and only run once.
Inspired by PlagTag's idea.
In another way these code would tried:
ssh admin#192.168.1.1 "/jffs/your_script.sh &"
Simple and without any programs like nohup screen...
(BTW: worked on Asus-Merlin firmware)
Try this:
nohup /root/wget/wget_download.sh >/dev/null 2>&1 &
It will go to the background so when you close your Putty session, it will be still running, and it won't send messages to the terminal.
I placed a link to my scripts in the rc.local to autostart it on linux debian boot. It starts and then stops at the while loop. It's a netcat script that listens permantently on port 4001.
echo "Start"
while read -r line
do
#some stuff to do
done < <(nc -l -p 4001)
When I start this script as root with command ./myscript it works 100% correctly. Need nc (netcat) root level access or something else?
EDIT:
rc.local
#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.
/etc/samba/SQLScripts
exit 0
rc.local starts my script "SQLScripts"
SQLScripts
#! /bin/sh
# The following part always gets executed.
echo "Starting SQL Scripts" >> /var/log/SQLScriptsStart
/etc/samba/PLCCheck >> /var/log/PLCCheck &
"SQLScripts" starts "PLCCheck" (for example only one)
PLCCheck
#!/bin/bash
echo "before SLEEP" >> /var/log/PLCCheck
sleep 5
echo "after SLEEP" >> /var/log/PLCCheck
echo "vor While" >> /var/log/PLCCheck
while read -r line
do
echo "in While" >> /var/log/PLCCheck
done < <(netcat -u -l -p 6001)
In an rc script you have root level access by default. What does "it stops at the while loop" mean? It quits after a while, or so? I guess you need to run your loop in the background in order to achieve functionality usual in autostart scripts:
echo "Starting"
( while read -r line
do
#some stuff to do
done << (nc -l -p 4001) ) &
echo "Started with pid $( jobs -p )"
I have tested yersterday approximatly the same things, and I have discover that you can bypass the system and execute your netcat script with the following crontask. :
(every minute, but you can ajust that as you want.)
* * * * * /home/kali/script-netcat.sh // working for me
#reboot /home/kali/script-netcat.sh // this is blocked by the system.
According to me, I think that by default debian (and maybe others linux distrib) block every script that try to execute a netcat command.
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I have a #!/bin/bash file in cron.week directory.
Is there a way to test if it works? Can't wait 1 week
I am on Debian 6 with root
Just do what cron does, run the following as root:
run-parts -v /etc/cron.weekly
... or the next one if you receive the "Not a directory: -v" error:
run-parts /etc/cron.weekly -v
Option -v prints the script names before they are run.
A wee bit beyond the scope of your question... but here's what I do.
The "how do I test a cron job?" question is closely connected to "how do I test scripts that run in non-interactive contexts launched by other programs?" In cron, the trigger is some time condition, but lots of other *nix facilities launch scripts or script fragments in non-interactive ways, and often the conditions in which those scripts run contain something unexpected and cause breakage until the bugs are sorted out. (See also: https://stackoverflow.com/a/17805088/237059 )
A general approach to this problem is helpful to have.
One of my favorite techniques is to use a script I wrote called 'crontest'. It launches the target command inside a GNU screen session from within cron, so that you can attach with a separate terminal to see what's going on, interact with the script, even use a debugger.
To set this up, you would use "all stars" in your crontab entry, and specify crontest as the first command on the command line, e.g.:
* * * * * crontest /command/to/be/tested --param1 --param2
So now cron will run your command every minute, but crontest will ensure that only one instance runs at a time. If the command takes time to run, you can do a "screen -x" to attach and watch it run. If the command is a script, you can put a "read" command at the top to make it stop and wait for the screen attachment to complete (hit enter after attaching)
If your command is a bash script, you can do this instead:
* * * * * crontest --bashdb /command/to/be/tested --param1 --param2
Now, if you attach with "screen -x", you'll be facing an interactive bashdb session, and you can step through the code, examine variables, etc.
#!/bin/bash
# crontest
# See https://github.com/Stabledog/crontest for canonical source.
# Test wrapper for cron tasks. The suggested use is:
#
# 1. When adding your cron job, use all 5 stars to make it run every minute
# 2. Wrap the command in crontest
#
#
# Example:
#
# $ crontab -e
# * * * * * /usr/local/bin/crontest $HOME/bin/my-new-script --myparams
#
# Now, cron will run your job every minute, but crontest will only allow one
# instance to run at a time.
#
# crontest always wraps the command in "screen -d -m" if possible, so you can
# use "screen -x" to attach and interact with the job.
#
# If --bashdb is used, the command line will be passed to bashdb. Thus you
# can attach with "screen -x" and debug the remaining command in context.
#
# NOTES:
# - crontest can be used in other contexts, it doesn't have to be a cron job.
# Any place where commands are invoked without an interactive terminal and
# may need to be debugged.
#
# - crontest writes its own stuff to /tmp/crontest.log
#
# - If GNU screen isn't available, neither is --bashdb
#
crontestLog=/tmp/crontest.log
lockfile=$(if [[ -d /var/lock ]]; then echo /var/lock/crontest.lock; else echo /tmp/crontest.lock; fi )
useBashdb=false
useScreen=$( if which screen &>/dev/null; then echo true; else echo false; fi )
innerArgs="$#"
screenBin=$(which screen 2>/dev/null)
function errExit {
echo "[-err-] $#" | tee -a $crontestLog >&2
}
function log {
echo "[-stat-] $#" >> $crontestLog
}
function parseArgs {
while [[ ! -z $1 ]]; do
case $1 in
--bashdb)
if ! $useScreen; then
errExit "--bashdb invalid in crontest because GNU screen not installed"
fi
if ! which bashdb &>/dev/null; then
errExit "--bashdb invalid in crontest: no bashdb on the PATH"
fi
useBashdb=true
;;
--)
shift
innerArgs="$#"
return 0
;;
*)
innerArgs="$#"
return 0
;;
esac
shift
done
}
if [[ -z $sourceMe ]]; then
# Lock the lockfile (no, we do not wish to follow the standard
# advice of wrapping this in a subshell!)
exec 9>$lockfile
flock -n 9 || exit 1
# Zap any old log data:
[[ -f $crontestLog ]] && rm -f $crontestLog
parseArgs "$#"
log "crontest starting at $(date)"
log "Raw command line: $#"
log "Inner args: $#"
log "screenBin: $screenBin"
log "useBashdb: $( if $useBashdb; then echo YES; else echo no; fi )"
log "useScreen: $( if $useScreen; then echo YES; else echo no; fi )"
# Were building a command line.
cmdline=""
# If screen is available, put the task inside a pseudo-terminal
# owned by screen. That allows the developer to do a "screen -x" to
# interact with the running command:
if $useScreen; then
cmdline="$screenBin -D -m "
fi
# If bashdb is installed and --bashdb is specified on the command line,
# pass the command to bashdb. This allows the developer to do a "screen -x" to
# interactively debug a bash shell script:
if $useBashdb; then
cmdline="$cmdline $(which bashdb) "
fi
# Finally, append the target command and params:
cmdline="$cmdline $innerArgs"
log "cmdline: $cmdline"
# And run the whole schlock:
$cmdline
res=$?
log "Command result: $res"
echo "[-result-] $(if [[ $res -eq 0 ]]; then echo ok; else echo fail; fi)" >> $crontestLog
# Release the lock:
9<&-
fi
After messing about with some stuff in cron which wasn't instantly compatible I found that the following approach was nice for debugging:
crontab -e
* * * * * /path/to/prog var1 var2 &>>/tmp/cron_debug_log.log
This will run the task once a minute and you can simply look in the /tmp/cron_debug_log.log file to figure out what is going on.
It is not exactly the "fire job" you might be looking for, but this helped me a lot when debugging a script that didn't work in cron at first.
I'd use a lock file and then set the cron job to run every minute. (use crontab -e and * * * * * /path/to/job) That way you can just keep editing the files and each minute they'll be tested out. Additionally, you can stop the cronjob by just touching the lock file.
#!/bin/sh
if [ -e /tmp/cronlock ]
then
echo "cronjob locked"
exit 1
fi
touch /tmp/cronlock
<...do your regular cron here ....>
rm -f /tmp/cronlock
What about putting it into cron.hourly, waiting until the next run of hourly cron jobs, then removing it? That would run it once within an hour, and in the cron environment. You can also run ./your_script, but that won't have the same environment as under cron.
Aside from that you can also use:
http://pypi.python.org/pypi/cronwrap
to wrap up your cron to send you an email upon success or failure.
None of these answers fit my specific situation, which was that I wanted to run one specific cron job, just once, and run it immediately.
I'm on a Ubuntu server, and I use cPanel to setup my cron jobs.
I simply wrote down my current settings, and then edited them to be one minute from now. When I fixed another bug, I just edited it again to one minute from now. And when I was all done, I just reset the settings back to how they were before.
Example: It's 4:34pm right now, so I put 35 16 * * *, for it to run at 16:35.
It worked like a charm, and the most I ever had to wait was a little less than one minute.
I thought this was a better option than some of the other answers because I didn't want to run all of my weekly crons, and I didn't want the job to run every minute. It takes me a few minutes to fix whatever the issues were before I'm ready to test it again. Hopefully this helps someone.
The solution I am using is as follows:
Edit crontab(use command :crontab -e) to run the job as frequently
as needed (every 1 minute or 5 minutes)
Modify the shell script which should be executed using cron to prints the output into some file (e.g: echo "Working fine" >>
output.txt)
Check the output.txt file using the command : tail -f output.txt, which will print the latest additions into this file, and thus you can track the execution of the script
I normally test by running the job i created like this:
It is easier to use two terminals to do this.
run job:
#./jobname.sh
go to:
#/var/log and run
run the following:
#tailf /var/log/cron
This allows me to see the cron logs update in real time. You can also review the log after you run it, I prefer watching in real time.
Here is an example of a simple cron job. Running a yum update...
#!/bin/bash
YUM=/usr/bin/yum
$YUM -y -R 120 -d 0 -e 0 update yum
$YUM -y -R 10 -e 0 -d 0 update
Here is the breakdown:
First command will update yum itself and next will apply system updates.
-R 120 : Sets the maximum amount of time yum will wait before performing a command
-e 0 : Sets the error level to 0 (range 0 - 10). 0 means print only critical errors about which you must be told.
-d 0 : Sets the debugging level to 0 - turns up or down the amount of things that are printed. (range: 0 - 10).
-y : Assume yes; assume that the answer to any question which would be asked is yes
After I built the cron job I ran the below command to make my job executable.
#chmod +x /etc/cron.daily/jobname.sh
Hope this helps,
Dorlack
sudo run-parts --test /var/spool/cron/crontabs/
files in that crontabs/ directory needs to be executable by owner - octal 700
source: man cron and NNRooth's
I'm using Webmin because its a productivity gem for someone who finds command line administration a bit daunting and impenetrable.
There is a "Save and Run Now" button in the "System > Scheduled Cron Jobs > Edit Cron Job" web interface.
It displays the output of the command and is exactly what I needed.