I would like to prevent one of my root processes from deleting a certain file. So I came across the flock command, it seems to fit my need, but I didn't get its syntax.
If I only indicate a shared lock, it doesn't work:
flock -s "./file.xml"
If I add a timeout parameter, it still doesn't work:
flock -s -w5 "./file.xml"
It seems that way, it fits in
flock [-sxun][-w #] fd# way.
(What is this
So, I tried:
flock [-sxon][-w #] file [-c] command
flock -s -w5 "./file.xml" -c "tail -3 ./file.xml" and it worked, tail command at ./file.xml was executed.
But I would like to know, does the lock end after the command or does it last 5 seconds after the end of the command execution? My main question is, how can I prevent another root process from deleting a file in linux?