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Basic question regarding the ls utility. What do letters b and c mean at the beginning of the 10-symbol code describing the items' privileges?

From what I understand, when typing ls -l, the terminal provides a list of all items in a directory. Each item description is preceded by a 10-symbol code. This code says what the item type is (first symbol) and what the item privileges for the user, the user group and all other users are.

  • If the first symbol is a dash -, the item is a file.

  • If the first symbol is the letter d, the item is a directory.

  • If the first symbol is letter l, the item is a link / shortcut.

For example:

$ ls -l /home/phodor
total 68
drwxr-xr-x 5 phodor phodor 4096 Dec 20 12:02 Documents
drwxr-xr-x 9 phodor phodor 4096 Jan 17 12:02 Desktop
drwxr-xr-x 7 phodor phodor 4096 Jan 13 22:42 Downloads
-rw-r--r-- 1 phodor phodor 8980 Jun 27  2015 hello.txt
lrwxrwxrwx 1 phodor phodor   29 Jan 17 12:02 MyEBook -> /home/phodor/Documents/EBook.pdf

However some the 10-symbol code can also start with b or c for some items:

$ ls -l /dev
crw--w---- 1 root tty  4, 0 Jan 17 09:19 tty0
brw-rw---- 1 root disk 1, 0 Jan 17 09:19 ram0
brw-rw---- 1 root disk 8, 0 Jan 17 09:19 sda

What do b and c mean? What is the full list of values that the first symbol of the file description code can take (-, d, l, b, c, ...)?

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1 Answer 1

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From section 10.1.2 What information is listed of the GNU Coreutils 9.0 manual:

The file type is one of the following characters:

‘-’

    regular file 
‘b’

    block special file 
‘c’

    character special file 
‘C’

    high performance (“contiguous data”) file 
‘d’

    directory 
‘D’

    door (Solaris) 
‘l’

    symbolic link 
‘M’

    off-line (“migrated”) file (Cray DMF) 
‘n’

    network special file (HP-UX) 
‘p’

    FIFO (named pipe) 
‘P’

    port (Solaris) 
‘s’

    socket 
‘?’

    some other file type
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    where "special file" means it is a device node, as created using mknod(). These are the interfaces to the kernel for various device drivers. Commented Jan 17, 2016 at 17:44

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