I have a bash script with a loop of processes that I want to run in parallel:
for i in {1..5}
do
echo Running for simulation $i
python script.py $i > ./outlogs/$i.log 2>&1 &
done
But when I do this the file redirection doesn't work, so $i.log just stays empty. The redirection only works when I do not use the & at the end, but then the script waits for each process to finish before starting the next one, which I don't want.
I tried a solution using script -c, but this does not update in realtime, only once the process ends. Does anyone have better suggestions, where the file redirection works in this script but it still updates in realtime?
You need simply add -u option so it will look like this:
python -u script.py $i > ./outlogs/$i.log 2>&1 &
Option -u is for unbuffered binary stdout and stderr
Related
I'm wrote a bash script and I don't have a chance to download pssh. However, I need to run multiple ssh commands in parallel. There is no problem so far, but when I run ssh commands, I want to see the outputs sequentially from the remote machine. I mean one ssh has multiple outputs and they get mixed up because more than one ssh is running.
#!/bin/bash
pid_list=""
while read -r list
do
ssh user#$list 'commands'&
c_pid=$!
pid_list="$pid_list $c_pid"
done < list.txt
for pid in $pid_list
do
wait $pid
done
What should I add to the code to take the output unmixed?
The most obvious way to me would be to write the outputs in a file and cat the files at the end:
#!/bin/bash
me=$$
pid_list=""
while read -r list
do
ssh user#$list 'hostname; sleep $((RANDOM%5)); hostname ; sleep $((RANDOM%5))' > /tmp/log-${me}-$list &
c_pid=$!
pid_list="$pid_list $c_pid"
done < list.txt
for pid in $pid_list
do
wait $pid
done
cat /tmp/log-${me}-*
rm /tmp/log-${me}-* 2> /dev/null
I didn't handle stderr because that wasn't in your question. Nor did I address the order of output because that isn't specified either. Nor is whether the output should appear as each host finishes. If you want those aspects covered, please improve your question.
I have little experiences in shell commands in unix.
So far, I have checked stackOverflow and know how to run simple shell scripts in order by
using echo
echo $(sh dosomthing1.sh)
echo $(sh dosomthing2.sh)
directly using sh xxx and wait
sh dosomthing1.sh
wait
sh dosomthing2.sh
using &&
sh dosomthing1.sh && sh dosomthing2.sh
But these ways seem to be helpless to solve my problem...
Here is my problem:
I have a basic shell script to do a maven compile and then using "nohup xxx &" to start a java application in background. the script is shown below:
#get the input env parameter
env=$1
#goto application root directory
cd /applicationDir
#to compile
mvn install -Dmaven.test.skip=true
#to start with parameter env
nohup java -jar -Dspring.profiles.active=$env myApplication.jar &
#to tail the log
tail -20f myApplication.log
I have too many different applications with the same startup scripts and it is hard to start them one by one. I need to start them with one command.
All the shell scripts are expected to be processed one by one in order. If there are any exceptions, skip and run the next one.
And when I tried to write a script like this:
sh start1.sh
wait
echo "application 1 was start up"
sh start2.sh
wait
echo "application 2 was start up"
...
sh startxxx.sh
wait
echo "application xxx was start up"
Though all the children shell scripts will process in order as what I expected, and the output infomations looked like the shell is functioning well, but the fact is only the last application will be started, all the previous command "nohup xxxx &" will be shut down.
Also I have tried to write like this:
sh start1.sh &
sh start2.sh &
...
sh startxxx.sh &
Although the result was what I want, all the application will be started well, but during processing the scripts, because of the parallel running of the scripts, the consoled output is unreadable. It comes to a good result but not a graceful way.
I have no idea how to solve this problem...
Please help me with this, thank you very much!
When you have a script with commands, you cam do chmod +x start.sh. Now the script can be started with ./start.sh. You will avoid an additional sh process and with ls -l you can see which scripts are executable.
In your scripts you have tail -f. This will be very confusing for a backgound process. Start the scripts in the background and view the logging from the console. I do hope that each script is using a different myApplication.jar and myApplication.log.
When the logging in the logfile is duplicated in stdout (your commandline window), you can throw that logging away.
./start1.sh > /dev/null 2>&1 &
./start2.sh > /dev/null 2>&1 &
./startxxx.sh > /dev/null 2>&1 &
The processes will be killed when you logout before the scripts are terminated. This can be avoided with nohup:
nohup ./start1.sh > /dev/null 2>&1 &
nohup ./start2.sh > /dev/null 2>&1 &
nohup ./startxxx.sh > /dev/null 2>&1 &
Edit:
OPS wants to start programs in a fixed order.
Starting scripts exactly one after another in order, should be possible by calling them in the right order (perhaps with an additional sleep 1).
When you need to wait for program 1 finished some init stuff, you need to check that. Use 1 script calling all scripts and add some control statements, like
nohup java something &
while ! grep -q "Started" myApplication.log; do
sleep 1
done
When the java program has an error the while will wait for ever, so replace this with some max retrycount
for ((retry=0l retry<100; retry++)); do
grep -q "Started" myApplication.log && break
sleep 1
done
https://man7.org/linux/man-pages/man8/cron.8.html
This might help you. Cron is a task scheduler, which you can use to run programs in sequence. If the man page is difficult to understand, look for tutorials on it; I'm sure some would exist.
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.
This is the first question that I post here. I tried to do a throughout search, but if I haven't (and the answer is obvious somewhere else), please just let me know.
I have a script that runs a program for me, here it is:
csv_file=../data/teste_nohup.csv
trace_file=../data/gnp.trace
declare -i n=100
declare -i p=1
declare -i counter=0
while [ $counter -lt 3 ];
do
n=100
while true
do
nice -19 sage gnptest.py ${n} ${p} | tee -a ${csv_file}
notify-send "finished test gnp ${n} ${p}"
done
done
So, what I'm trying to do is run the gnptest.py program a few times, and have the result be written to the csv_file.
The problem is, that depending on the input, the program may take a long time to complete. So I'd like to connect to the server over ssh, start the program, close the terminal, and check the output file from time to time.
I've tried nohup and disown. Nohup creates a huge nohup.out file, full with errors that I don't get while normally running the script (it complains about using the -lt operand, for example). But the biggest problem that I'm facing is that no command (nohup ou disown -h) is executing the program and sending the output to the file that I've specified in the csv_file variable, which is being done using the tee command. Also, none of them seem to continue running after I logout...
Any help will be much appreciated.
Thanks in advance!!
i hv just joined so cannt add comment
Please try by using redirection instead of tee in script
And to get rid of Nohup.out use following to run script
nohup script.sh > /dev/null 2>&1 &
If above produces error use
nohup script.sh > /dev/null 2>&1 </dev/null &
Hope this will help.
I have a basic script that outputs various status messages. e.g.
~$ ./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.