Processes accessing a file

'fuser' command can be used to get the processes that are accessing the file.

'fuser /tmp/hello.txt' - lists the process ids of all the processes accessing the file '/tmp/hello.txt'.

You need to have the required permission. root can view all the processes that are accessing the file.

fuser can also be used if you want to kill (send signal) the process that is accessing the file. The option for that is -k.