Shell script does not work when run as daemon - linux

I got a simple script (to measure CPU overhead)
#!/bin/bash
WAIT=2
i=1
while :
do
# Obtain the cpu usage
top -n 1 > t.$i
i=$(($i+1))
sleep $WAIT
done
When I run it as
./Script.sh
It works as expected.
But when I run it as
./Script.sh&
it does nothing (files are not created). What am I missing here?

Change the line where you invoke top to be:
top -b -n 1 > t.$i
This enables batch mode - good call Karoly

Related

program self loops in shell script, but want script to control looping

I have a shell script (plotter.sh) that runs a program that currently loops infinitely on it's own (see below). The problem is when I want to tweak the program's options/syntax I typically wait until a loop is complete, stop the script, make my tweaks to the program's options and start the script again. The program does have an option to run once. With that said, how do I set it up so the shell script controls the looping and I can make changes to the program's options on the fly, the program automatically runs with the new changes on the subsequent loop - all without having to stop anything?
#!/bin/bash
#VARIABLES
poolcontactaddress=gjghkjhj
farmerpublickey=gjhgjhgjhgjh
farmid=${farmerpublickey: -6}
timestamp=$(date +'%Y%m%d-%H%M%S')
loopid=$(uuid)
#runid=$(uuid)
~/chia/chia-plotter/build/chia_plot -c $poolcontactaddress -f $farmerpublickey -t /mnt/u2-0052/ -2 /mnt/ramdisk/ -n -1 -r 48 -u 128 2>&1 | tee ~/chia/logs/plotter-$farmid-$loopid-$timestamp.log;

Is it possible to auto reboot for 5 loops through mint?

I am currently using the following command to run reboot
sudo shutdown -r now
however, I would need to run it for 5 loops before and after executing some other programs. Was wondering if it is possible to do it in MINT environment?
First a disclaimer: I haven't tried this because I don't want to reboot my machine right now...
Anyway, the idea is to make a script that can track it's iteration progress to a file as #david-c-rankin suggested. This bash script could look like this (I did test this):
#!/bin/sh
ITERATIONS="5"
TRACKING_FILE="/path/to/bootloop.txt"
touch "$TRACKING_FILE"
N=$(cat "$TRACKING_FILE" | wc -c)
if [ "$N" -lt "$ITERATIONS" ]; then
printf "." >> "$TRACKING_FILE"
echo "rebooting (iteration $N)"
# TODO: this is where you put the reboot command
# and anything you want to run before rebooting each time
else
rm "$TRACKING_FILE"
# TODO: other commands to resume anything required
fi
Then add a call to this script somewhere where it will be run on boot. eg. cron (#reboot) or systemd. Don't forget to remove it from a startup/boot command when you're finished or next time you reboot, it will reboot N times.
Not sure exactly how you are planning on using it, but the general workflow would look like:
save script to /path/to/reboot_five_times.sh
add script to run on boot (cron, etc.)
do stuff (manually or in a script)
call the script
computer reboots 5 times
anything in the second TODO section of the script is then run
go back to step 3, or if finished remove from cron/systemd so it won't reboot when you don't want it to.
First create a text document wherever you want,I created one on Desktop,
Then use this file as a physical counter and write a daemon file to run things at startup
For example:
#!/bin/sh
var=$(cat a.txt)
echo "$var"
if [ "$var" != 5 ]
then
var=$((var+1))
echo "$var" > a.txt
echo "restart here"
sudo shutdown -r now
else
echo "stop restart"
echo 0 > a.txt
fi
Hope this helps
I found a way to create a file at startup for my reboot script. I incorporated it with the answers provided by swalladge and also shubh. Thank you so much!
#!/bin/bash
#testing making a startup application
echo "
[Desktop Entry]
Type=Application
Exec=notify-send success
Hidden=false
NoDisplay=false
X-GNOME-Autostart-enabled=true
Name[en_CA]=This is a Test
Name=This is a Test
Comment[en_CA]=
Comment=" > ~/.config/autostart/test.desktop
I create a /etc/rc.local file to execute user3089519's script, and this works for my case. (And for bootloop.txt, I put it here: /usr/local/share/bootloop.txt )
First: sudo nano /etc/rc.local
Then edit this:
#!/bin/bash
#TODO: things you want to execute when system boot.
/path/to/reboot_five_times.sh
exit 0
Then it works.
Don't forget edit /etc/rc.local and remove /path/to/reboot_five_times.sh when you done reboot cycling.

Ending an mpirun process terminates a bash loop

I'm trying to schedule a series of mpi jobs on an Ubuntu 14.04 LTS machine using a bash script. Basically, I want a simulation to run on every core for a certain amount of time, then terminate and move on to the next case once that time has elapsed.
My issue arises when mpi exits at the end of the first job - it breaks the loop and returns the terminal to my control instead of heading onto the next iteration of the loop.
My script is included below. The file "case_names" is just a text file of directory names. I've tested the script with other commands and it works fine until I uncomment the mpirun call.
#!/bin/bash
while read line;
do
# Access case dierctory
cd $line
echo "Case $line accessed"
# Start simulation
echo "Case $line starting: $(date)"
mpirun -q -np 8 dsmcFoamPlus -parallel > log.dsmcFoamPlus &
# Wait for 10 hour runtime
sleep 36000
# Kill job
pkill mpirun > /dev/null
echo "Case $line terminated: $(date)"
# Return to parent directory
cd ..
done < case_names
Does anyone know of a way to stop mpirun from breaking the loop like this?
So far I've tried GNOME task scheduler and task-spooler, but neither have worked (likely due to aliases that have to be invoked before the commands I use become available). I'd really rather not have to resort to setting up slurm. I've also tried using the disown command to separate the mpi process from the shell I'm running the scheduling script in, and have even written a separate script just to kill processes which the scheduling script runs remotely.
Many thanks in advance!
I've managed to find a workaround that allows me to schedule tasks with a bash script like I wanted. Since this solves my issue, I'm posting it as an answer (although I would still welcome an explanation as to why mpi behaves in this way in loops).
The solution lay in writing a separate script for both calling and then killing mpi, which would itself be called by the scheduling script. Since this child bash process has no loops in it, there are no issues with mpi breaking them after being killed. Also, once this script has exited, the scheduling loop can continue unimpeded.
My (now working) code is included below.
Scheduling script:
while read line;
do
cd $line
echo "CWD: $(pwd)"
echo "Case $line accessed"
bash ../run_job
echo "Case $line terminated: $(date)"
cd ..
done < case_names
Execution script (run_job):
mpirun -q -np 8 dsmcFoamPlus -parallel > log.dsmcFoamPlus &
echo "Case $line starting: $(date)"
sleep 600
pkill mpirun
I hope someone will find this useful.

Run a script in the same shell(bash)

My problem is specific to the running of SPECCPU2006(a benchmark suite).
After I installed the benchmark, I can invoke a command called "specinvoke" in terminal to run a specific benchmark. I have another script, where part of the codes are like following:
cd (specific benchmark directory)
specinvoke &
pid=$!
My goal is to get the PID of the running task. However, by doing what is shown above, what I got is the PID for the "specinvoke" shell command and the real running task will have another PID.
However, by running specinvoke -n ,the real code running in the specinvoke shell will be output to the stdout. For example, for one benchmark,it's like this:
# specinvoke r6392
# Invoked as: specinvoke -n
# timer ticks over every 1000 ns
# Use another -n on the command line to see chdir commands and env dump
# Starting run for copy #0
../run_base_ref_gcc43-64bit.0000/milc_base.gcc43-64bit < su3imp.in > su3imp.out 2>> su3imp.err
Inside it it's running a binary.The code will be different from benchmark to benchmark(by invoking under different benchmark directory). And because "specinvoke" is installed and not just a script, I can not use "source specinvoke".
So is there any clue? Is there any way to directly invoke the shell command in the same shell(have same PID) or maybe I should dump the specinvoke -n and run the dumped materials?
You can still do something like:
cd (specific benchmark directory)
specinvoke &
pid=$(pgrep milc_base.gcc43-64bit)
If there are several invocation of the milc_base.gcc43-64bit binary, you can still use
pid=$(pgrep -n milc_base.gcc43-64bit)
Which according to the man page:
-n
Select only the newest (most recently started) of the matching
processes
when the process is a direct child of the subshell:
ps -o pid= -C=milc_base.gcc43-64bit --ppid $!
when not a direct child, you could get the info from pstree:
pstree -p $! | grep -o 'milc_base.gcc43-64bit(.*)'
output from above (PID is in brackets): milc_base.gcc43-64bit(9837)

Redirecting Output of Bash Child Scripts

I have a basic script that outputs various status messages. e.g.
~$ ./myscript.sh
0 of 100
1 of 100
2 of 100
...
I wanted to wrap this in a parent script, in order to run a sequence of child-scripts and send an email upon overall completion, e.g. topscript.sh
#!/bin/bash
START=$(date +%s)
/usr/local/bin/myscript.sh
/usr/local/bin/otherscript.sh
/usr/local/bin/anotherscript.sh
RET=$?
END=$(date +%s)
echo -e "Subject:Task Complete\nBegan on $START and finished at $END and exited with status $RET.\n" | sendmail -v group#mydomain.com
I'm running this like:
~$ topscript.sh >/var/log/topscript.log 2>&1
However, when I run tail -f /var/log/topscript.log to inspect the log I see nothing, even though running top shows myscript.sh is currently being executed, and therefore, presumably outputting status messages.
Why isn't the stdout/stderr from the child scripts being captured in the parent's log? How do I fix this?
EDIT: I'm also running these on a remote machine, connected via ssh using pseudo-tty allocation, e.g. ssh -t user#host. Could the pseudo-tty be interfering?
I just tried your the following: I have three files t1.sh, t2.sh, and t3.sh all with the following content:
#!/bin/bash
for((i=0;i<10;i++)) ; do
echo $i of 9
sleep 1
done
And a script called myscript.sh with the following content:
#!/bin/bash
./t1.sh
./t2.sh
./t3.sh
echo "All Done"
When I run ./myscript.sh > topscript.log 2>&1 and then in another terminal run tail -f topscript.log I see the lines being output just fine in the log file.
Perhaps the things being run in your subscripts use a large output buffer? I know when I've run python scripts before, it has a pretty big output buffer so you don't see any output for a while. Do you actually see the entire output in the email that gets sent out at the end of topscript.sh? Is it just that while the processes run you're not seeing the output?
try
unbuffer topscript.sh >/var/log/topscript.log 2>&1
Note that unbuffer is not always available as a std binary in old-style Unix platforms and may require a search and installation for a package to support it.
I hope this helps.

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