How to know if a folder is being written with a file at any point of time?

MaRock · 08-21-2008, 02:10 AM

hi all,

how do i find if somefile is being written to a folder at any point in time. i.e in other words , i want to know if a file being written to a folder is done or is still being done.
eg: i copy file 'x' to folder 'Y' now i want to copy x into another folder 'Z' but i want to make sure that 'x' is completely copied to the folder 'Y' before the file is copied from 'Y' to 'Z'. is there a command or code logic which will tell me if the write is done or not?

--Maneesh

jschiwal · 08-21-2008, 02:17 AM

cp x/file y/ && cp x/file z/

MaRock · 08-21-2008, 02:31 AM

Quote:

Originally Posted by jschiwal

cp x/file y/ && cp x/file y/

will try this out..
thank u

MaRock · 08-21-2008, 02:34 AM

Quote:

Originally Posted by jschiwal

cp x/file y/ && cp x/file y/

hi jschiwal ,

Can u pls explain how this works?

jschiwal · 08-22-2008, 12:40 AM

The "&&" stands for and. If the first command is successful, the next command is run. Otherwise it is skipped.

I meant to write "cp x/file y/ && cp x/file z/". Since the source is the same you don't need to copy from y/. If y/ is a mounted share and you want to move it if someone else (or another process) is finished writing, you could look at the output of lsof and not copy a file if it is listed. You could also use the find command and check if the mtime value is more than a certain amount of time.

One of the fields will indicate the type of access. If the access is "read" than it would be ok to copy it. If the access is write, then you may want to wait.

Code:

lsof | grep pod
amarokapp 16769   jschiwal   20r      REG               0,19 11248947 19111954 /mnt/hpmedia/podcasts/Slashdot Review - SDR News/SDR2008-08-22.mp3 (hpmedia.jesnet:/home/jschiwal/podcasts)

Code:

lsof | grep pod | awk '$4 ~ /r/ {print $9}'
/mnt/hpmedia/podcasts/Slashdot
jschiwal@qosmio:~> lsof | grep pod | awk '$4 ~ /w/ {print $9}'

MaRock · 08-22-2008, 01:26 AM

Thanks

this was exactly what i was looking for..
great help

MaRock · 08-22-2008, 02:30 AM

jschiwal,
i have one more question...

Now suppose i write a script, now i want it to run at regular intervals (with out scheduling it in crontab) .. in other words i write a daemon / init script.. how do i achieve this?

vikas027 · 08-25-2008, 12:43 AM

Quote:

Originally Posted by MaRock

jschiwal,
i have one more question...

Now suppose i write a script, now i want it to run at regular intervals (with out scheduling it in crontab) .. in other words i write a daemon / init script.. how do i achieve this?

To run a script at regular intervals I believe you will have to use crontab.

Or else you can use run this command in a script say rc.local

Code:

((while true;do date; sleep 10; done;) >> /any/file ) &

This can help you out... it would start running when all of your default scripts would stop executing and would redirect the output in any file in the background.

Hope this helps.

MaRock · 08-25-2008, 05:40 AM

Thanks Vikas !