Visit Our UNIX and Linux User Community

Many processes running at the same time

Thread Tools Search this Thread
Top Forums UNIX for Beginners Questions & Answers Many processes running at the same time
# 1  
Old 02-12-2018
Many processes running at the same time

Hello everybody ,

I launched cron to execute a task every hour but the job takes more than hour that's why I'm getting more than 1000 cron processes running at the same time !!!
My question is how to tell cron not to execute unless the job terminated in order to have only one process running .
Thanks in advance
# 2  
Old 02-12-2018
Create your own 'flag'. For example, when the job finishes, the last thing it does is create a file called 'oktorun'. The first thing the job does when it starts is check for the existence of the file 'oktorun' and, if it does not exist then do nothing and terminate. If the file does exist then delete it and run the job. So the file does not exist whilst a job is running.

Anyway, if you're happy for a job to start immediately after the previous one finishes then why not get it to spawn itself (without the use of cron) ?

Last edited by hicksd8; 02-12-2018 at 08:42 AM..
This User Gave Thanks to hicksd8 For This Post:
# 3  
Old 02-12-2018
first of all I wanna thank you for your answer ,
but to be honest I have no idea how to create this file , where to put it and what should I put inside.
same for the second hypothesis
# 4  
Old 02-12-2018
Hmmm - something seems to be wrong here. 1000 jobs, started one per hour, would be 41 days worth of jobs - if not a single job finished in the meantime. Are you sure everything is correct with your script / program? Is it expected to finish in close to an hour? Does it finish at all? Are there locking problems?
This User Gave Thanks to RudiC For This Post:
# 5  
Old 02-12-2018
@RudiC......Good thinking.
@beautymind......Please post the script you are using.
# 6  
Old 02-12-2018
One example of using a flag, or lock file.
if [[ -f /tmp/${myname} ]] 
    if ps -p ${myname_proc} >/dev/null
    then exit
    else rm  /tmp/${myname} # assumption: last iteration of program died
echo $$ > /tmp/${myname}
cleanup() {
    trap '' 0 HUP INT QUIT ABRT TERM # clear traps
    rm /tmp/${myname}
    # other cleanup here
trap 'cleanup' 0 # always run cleanup on exit
trap 'exit' HUP INT QUIT ABRT TERM # exit on one of these signals
# the rest of your script goes here

A good place to put such a file is the /tmp directory. The cleanup function should ensure that the file is deleted on exit, so you don't have to remember to put
rm /tmp/${myname}

everywhere you exit the program. Putting the PID in the file and then checking whether the process exists is optional, and there in case the program exits abnormally, leaving the file in place.

This User Gave Thanks to apmcd47 For This Post:
# 7  
Old 02-12-2018
@RudiC , I don't know what is the problem because is it expected to finish in close to an hour.

Previous Thread | Next Thread
Test Your Knowledge in Computers #228
Difficulty: Easy
According to NetMarketShare, in September 2019 Linux had a 5% global market share of the desktop / laptop computer market.
True or False?

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Processes running response time

Hi All I have been asked to write scripts within our monitoring tool for a vast requirement set. One of the requirements is below: Lowest, Highest & Average response times of the Documentum process threads serving client requests Essentially they want a view where we can see the... (4 Replies)
Discussion started by: simpsa27
4 Replies

2. Shell Programming and Scripting

Multi threading - running multiple processes at the same time

so i've been using this a lot in a lot of my scripts: ( columnA & columnAPID=$! & columnB & columnBPID=$! & columnC & columnCPID=$! &) & wait ${columnAPID} wait ${columnBPID} wait ${columnCPID} It seems to work as ive seen it dramatically reduce run time of my scripts. however, i'm... (5 Replies)
Discussion started by: SkySmart
5 Replies

3. Linux

Running processes

Hi guys is it normal to have 5-10 cron/syslog processes running... in my case i got 10 cron process running. (4 Replies)
Discussion started by: batas
4 Replies

4. Solaris

Running processes on GZ/LZ

Hi guys just a question is it normal to see running process on a non-global zone in the global zone... processes such as cron. (3 Replies)
Discussion started by: batas
3 Replies

5. Shell Programming and Scripting

how to know the running processes.

Hi can anybody help me regarding this.. i want know the output of ps -ef with explanation. how can we know the running processess. this is the output of ps -elf F S UID PID PPID C PRI NI ADDR SZ WCHAN STIME TTY TIME CMD 19 T root 0 0 0 0 SY ... (1 Reply)
Discussion started by: rajesh_pola
1 Replies

6. Shell Programming and Scripting

determine the active processes on the system which are running since long time

Hi , Please help me shell script to determine the active processes on the system which are running since long time (2 Replies)
Discussion started by: itian2010
2 Replies

7. Shell Programming and Scripting

Help in running two processes in parellel

I have a script something like this: #!/usr/bin/ksh CLASSPATH=/apps/opt/db2udb/admin/db2bdt/sqllib/java/$CLASSPATH export CLASSPATH ... (7 Replies)
Discussion started by: ss3944
7 Replies

8. Solaris

About running processes in background

Hi, I need to establish a procedure that will start an application in background each time my remote Solaris server is (re)started. This would be a kind of daemon. I am no sysadmin expert, so I am looking for pointers. How should I proceed? What are the main steps? Thanks, JVerstry (9 Replies)
Discussion started by: JVerstry
9 Replies

9. Shell Programming and Scripting

monitoring running processes

I have a script that runs continuously and will deliver a file to multiple servers via scp. On occasions one of the scp's will hang and as a result not complete in sending the remaining files and not loop around again. If I run the scp commands with a & they'll complete, but I want to make sure... (2 Replies)
Discussion started by: nhatch
2 Replies

10. Programming

parsing currently running processes

Hey guys, I'm writing a monitoring program that reads the pattern and the max and min number of instances of a process and then proceeds to parse the currently running processes for the pattern. I just want to know how I should go about this. I'll give you an idea of the flow of the program:... (7 Replies)
Discussion started by: blowtorch
7 Replies

Featured Tech Videos