# lsfd > List open files and the corresponding processes in Linux. > More information: . - List all open file descriptors: `lsfd` - List all files kept open by a specific program: `lsfd {{-Q|--filter}} 'PID == {{process_ID}}'` - Check what program has a specific file open: `lsfd {{-Q|--filter}} "NAME == '{{/path/to/file}}'"` - List open IPv4 or IPv6 sockets: `lsfd -i{{4|6}}`