1
00:00:00,530 --> 00:00:04,520
In the last video, we showed you
a command that could create directories.

2
00:00:04,520 --> 00:00:08,618
But although you can name files and
directories almost anything you want,

3
00:00:08,618 --> 00:00:10,178
the wrong name can confuse or

4
00:00:10,178 --> 00:00:13,247
inconvenience other users
who need to access the file.

5
00:00:13,247 --> 00:00:15,852
To help avoid this,
some conventions for file and

6
00:00:15,852 --> 00:00:18,530
directory names have been
created over the years.

7
00:00:19,580 --> 00:00:23,810
File names are case sensitive
on Windows and Linux systems.

8
00:00:23,810 --> 00:00:26,720
For example, I can make a Park
directory with a capital P.

9
00:00:28,240 --> 00:00:31,350
If I list files now,
you'll see two park directories.

10
00:00:31,350 --> 00:00:35,820
One in all lower case and
one starting with a capital letter.

11
00:00:35,820 --> 00:00:41,340
This would not be true on Mac OS,
which uses a case insensitive file system.

12
00:00:41,340 --> 00:00:44,840
A Mac would have complained that the park
directory already exists because of

13
00:00:44,840 --> 00:00:46,060
the lower case version.

14
00:00:46,060 --> 00:00:49,910
It would not let me create
an additional uppercase version.

15
00:00:49,910 --> 00:00:52,550
Uppercase letters are always legal to use,
but

16
00:00:52,550 --> 00:00:57,040
to help avoid confusion you should stick
to all lower case letters in file names,

17
00:00:57,040 --> 00:01:00,440
regardless of what
operating system you use.

18
00:01:00,440 --> 00:01:04,300
Most file systems allow unicode
characters in file names now, but

19
00:01:04,300 --> 00:01:08,430
the special characters cause
problems on older file systems.

20
00:01:08,430 --> 00:01:12,360
If you're creating a file or a directory
you intend to share, you should stick to

21
00:01:12,360 --> 00:01:16,360
ASCII characters, unaccented
characters from the English alphabet.

22
00:01:17,460 --> 00:01:21,254
Numbers are fine anywhere
in the file name.

23
00:01:21,254 --> 00:01:25,030
I can make a directory named
1st_directory with a 1 at the start.

24
00:01:26,300 --> 00:01:29,722
I can make another directory named
directory_2 with a 2 at the end.

25
00:01:32,044 --> 00:01:36,160
Punctuation other than dashes and
underscores should be avoided.

26
00:01:36,160 --> 00:01:39,940
A period or a dot is okay
before the file extension, but

27
00:01:39,940 --> 00:01:41,740
should otherwise be avoided.

28
00:01:41,740 --> 00:01:44,379
A dot at the start of a file
name makes the file hidden.

29
00:01:45,810 --> 00:01:50,260
Spaces are legal in file or directory
names, but you should avoid them.

30
00:01:50,260 --> 00:01:54,153
Let me change to the library directory's
fiction subdirectory to demonstrate.

31
00:01:57,386 --> 00:02:02,188
Let's say I wanted to create a directory
for the author Peter F Hamilton.

32
00:02:02,188 --> 00:02:05,400
mkdir peter f hamilton.

33
00:02:05,400 --> 00:02:10,030
If I list files now, you'll see there
are three new separate directories.

34
00:02:10,030 --> 00:02:13,080
There they are, peter, f, and hamilton.

35
00:02:14,510 --> 00:02:18,470
That is definitely not what we wanted,
so let me get rid of those.

36
00:02:18,470 --> 00:02:22,715
Remove recursively f/ hamilton, and peter.

37
00:02:26,162 --> 00:02:30,047
I can create a single directory with
spaces in the name by surrounding it

38
00:02:30,047 --> 00:02:30,710
in quotes,

39
00:02:30,710 --> 00:02:32,970
so it's treated as a single argument.

40
00:02:32,970 --> 00:02:35,711
mkdir "peter f
hamilton" with quotes.

41
00:02:37,675 --> 00:02:42,336
Listing file shows just one new directory,
peter f hamilton.

42
00:02:42,336 --> 00:02:46,432
But unless I also surround the directory
name with quotes when attempting to change

43
00:02:46,432 --> 00:02:48,129
into it or otherwise work with it,

44
00:02:48,129 --> 00:02:52,970
the command will fail because the name
gets treated as three separate arguments.

45
00:02:52,970 --> 00:02:54,470
So that's not going to work well.

46
00:02:54,470 --> 00:02:55,990
Let me get rid of that directory.

47
00:02:55,990 --> 00:02:59,583
Remove, recursively,
quote peter f hamilton, end quote.

48
00:03:01,999 --> 00:03:05,772
Instead if a file or
directory name has multiple words,

49
00:03:05,772 --> 00:03:11,165
it's better to separate them with
underscores, mkdir peter_f_hamilton.

50
00:03:13,367 --> 00:03:20,377
Or sometimes you'll see dashes used
instead, mkdir peter-f-hamilton.

51
00:03:20,377 --> 00:03:24,850
This makes it clear that the whole file or
directory name is a single argument.

52
00:03:24,850 --> 00:03:28,680
To avoid confusion, you should pick one
of these two standards and stick with it.

53
00:03:28,680 --> 00:03:29,945
Don't mix the two.

54
00:03:29,945 --> 00:03:35,303
I am gonna go ahead and
get rid of the peter-f-hamilton directory.