Checking a file is not being written to - Shell Programming and Scripting

kanejm · #1 12-18-2005

Hello All

I am attempting to write a shell script (bourne shell script) which will copy a tar'd and compressed file from a directory to a staging area but will not know whether the file is still open for write since files are being ftp's to my site at random times during the day.

Once I am convinced that the file is stable (not being written to) I will move it to another directory, uncompress it and untar it and then process the data.

What is a good way to determine that the file is not being written to (ftp from other site is complete) before I move it out of the directory in which it was ftp'd into.

thanks
Joe

p.s. please respond by email: EMAIL ADDRESS REMOVED

Corona688 · #2 12-18-2005

From the rules you forgot to read:

Quote:

(10) Don't post your email address and ask for an email reply. The forums are for the benefit of all, so all Q&A should take place in the forums.

As for the question itself, that's tricky. Cooperative locking is possible, but both the shell and the FTP program would need to impliment that.

ranj@chn · #3 12-19-2005

Let the job which ftp's create a trigger file(with some unique pattern) after it is done with the ftp. This would give you an idea of the completion of the file transfer.

vino · #4 12-19-2005

This has worked for me in the past.

Code:

lsof /path/2/file/getting/modified

An exit code of 0 shows file in use. 1 shows no activity on that file.

Code:

[/tmp]$ /usr/sbin/lsof ~/temp/test.tar
COMMAND   PID    USER   FD   TYPE DEVICE      SIZE    NODE NAME
cp      22551 xxxxxxx    4w   REG    3,1 202321920 8798213 /private/ora/temp/test.tar
[/tmp]$ echo $?
0
[/tmp]$ /usr/sbin/lsof ~/temp/test.tar
[/tmp]$ echo $?
1
[/tmp]$

vino

mallikarjuna · #5 01-16-2006

Hi vino

please tell what is lsof.when ever i tried to as man lsof it is failing.my actual problm is clearly what kanejm has wrriten.

i tried like files=`lsof ${ALTAS_IN_DIR}/IINV*.* 2>/dev/null`
after that depends on files value means that is zero or one proceeding(move the files to other directory.).

but error is lsof not found.thats i want know about lsof.

Regards,
MallikarjunaRao

blowtorch · #6 01-16-2006

An error of 'lsof: not found' means that lsof is not available in your path. Check the value of the $PATH variable in your environment. Search for lsof on your box. Then add the path to lsof in the PATH variable in your environment. Here are the steps:
1.

Code:

echo $PATH

2.

Code:

whereis lsof

or (this may take quite a bit longer)

Code:

find /usr -name lsof -print

3.

Code:

PATH=$PATH:/path/to/lsof; export PATH

--EDIT--
mallikarjuna, in your code you are using *.* to pass filenames to lsof. I don't think that lsof can handle more than one filename at a time. Just check that out.
--/EDIT--

vino · #7 01-16-2006

What OS are you running ?

Post the results of uname -a

In my machine, lsof is /usr/sbin/lsof.

Follow what blowtorch says and you should find lsof.

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