help in wait or sleep command

nua7 · #1 (**permalink**) 09-25-2008

Hi All,
I have a script which runs 3 scripts. The first script creates two files. The other two scripts should run only when the files are created.

I tried the following for loop , but it is not working. Can someone please help me.

Code:

while [ ! -e script3.lck && script4.lck ]; do
# Sleep until file does exists/is created
sleep 1
done

era · #2 (**permalink**) 09-25-2008

Your "and" conditional is wrong, you need to repeat the -e

Code:

while [ ! -e script3.lck -a ! -e script4.lck ]; do

The && goes between two commands, like this:

Code:

while [ ! -e script3.lck ] && [ ! -e script4.lck ]; do

or you could change the flow entirely, to avoid those pesky negations:

Code:

while true; do
  test -e script3.lck && test -e script4.lck && break
  sleep 1
done

nua7 · #3 (**permalink**) 09-25-2008

Thanks a lot era! But in this case, even if one file is created , the while loop ends. Ideally it should end if both the files exist.

Any idea, where I have gone wrong..?

nua7 · #4 (**permalink**) 09-25-2008

whoops sorry for the confusion.. I tried your first suggestion, and it didn't work.

I tried your last suggestion, and works as a charm!!

Thanks a lot era!!!

era · #5 (**permalink**) 09-25-2008

Sorry, I guess precedence problem, the negation covers the whole of the following expression even across an -a apparently. In other words, the second ! in the first solution is wrong, and should be taken out. Another reason to avoid pesky negations I suppose ...

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