What is the trailing 'm' on fuser's output?-CodePudding

I'd like to list process' which use "/dev/my/dev". (Device name is an example) So I've used fuser:

$ fuser /dev/my/dev

/dev/my/dev:  19228m 19268 21620 21623 21663

Note the trailing 'm'.

If I redirect stderr, it's gone:

$ fuser /dev/my/dev 2>/dev/null 

 19228 19268 21620 21623 21663

What is this trailing 'm' doing here? Why is it reported to stderr?

fuser's version is:

$ fuser --version
fuser (PSmisc) 22.20
Copyright (C) 1993-2010 Werner Almesberger and Craig Small

Many thanks.

CodePudding user response：

The m signifies a memory-mapped (mmap) file or shared library.

fuser outputs only the PIDs to stdout, everything else is sent to stderr.

Hence, the behavior you see when STDERR is redirected to the bit-bucket.