file status question

[hanhaner]

hi, everyone

I am running many simulations, but need to update the same file from time to time.
Before one simulation reach the file, i have to garantee the other simulations are not updating the file. So does anyone know how to check the file' status before reach it? And how to make a short pause if the other simulations are updating it?
Thanks a lot!!!

han

[Motoma]

There is a standard way of doing this, it involves using a mutual exclusion semaphore (mutex).

[ghostdog74]

hi, everyone

I am running many simulations, but need to update the same file from time to time.
Before one simulation reach the file, i have to garantee the other simulations are not updating the file. So does anyone know how to check the file' status before reach it? And how to make a short pause if the other simulations are updating it?
Thanks a lot!!!

han

you can use fuser or lsof. I prefer lsof though. more powerful. an example

lsof -c "test.sh" #checks whether test.sh is being opened

if test.sh not opened, lsof return a 1. so you can catch this output using $? in the shell.