File types

Any on-disk file belongs to one of these types:
Regular file
Directory
Char device
Block device
Symbolic link
FIFO ("named pipe")
Socket

laptopo% mkfifo /tmp/fifo
laptopo% ls -Fld /bin/ls /tmp /tmp/fifo /dev/ttyS0 /dev/sda \
          /usr/bin/vi /tmp/.X11-unix/X0
-rwxr-xr-x 1 root   root     118280 Mar 14  2015 /bin/ls*
brw-rw---- 1 root   disk      8,  0 May  4 08:17 /dev/sda
crw-rw---- 1 root   dialout   4, 64 May  4 08:17 /dev/ttyS0
drwxrwxrwt 7 root   root    1138688 May  5 06:45 /tmp/
srwxrwxrwx 1 root   root          0 May  4 08:17 /tmp/.X11-unix/X0=
prw-rw-r-- 1 rubini staff         0 May  5 06:45 /tmp/fifo|
lrwxrwxrwx 1 root   root         20 Apr 26  2015 /usr/bin/vi ->
                      /etc/alternatives/vi*