20. lsof

me@box:~$ lsof | wc -l

lsof: WARNING: can't stat() fuse.gvfsd-fuse file system /run/user/1000/gvfs

Output information may be incomplete.

217071

me@box:~$ lsof -u www-data | head -n 5

lsof: WARNING: can't stat() fuse.gvfsd-fuse file system /run/user/1000/gvfs

Output information may be incomplete.

COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME

apache2 14644 www-data cwd DIR 8,65 4096 2 /

apache2 14644 www-data rtd DIR 8,65 4096 2 /

apache2 14644 www-data txt REG 8,65 662560 923195 /usr/sbin/apache2

apache2 14644 www-data mem REG 8,65 89696 131858 /lib/x86_64-linux-gnu/libgcc_s.so.1

FileDescriptor: current working dir, root dir, memory-mapped file, program text and data, etc