What does the $ sign mean when part of a file or folder name?

Question

I have folders that start with a $, like $Recycle.Bin, and folders that end with $, like C$.

Are these network shares?

Then again often I see files that otherwise look like dupes of files in the same folder, but they have a dollar sign somewhere in the name and they are greyed-out. What are those?

Answer 1

Network shares ending in $ are hidden: C$, IPC$.

Folders and files with names starting with $ are not in any way special. You may create your own:

C:\Users\rpresser>del $foo

C:\Users\rpresser>echo this is a dollar file >$foo

C:\Users\rpresser>dir *foo*
 Volume in drive C is OSDisk
 Volume Serial Number is 0263-7E64

 Directory of C:\Users\rpresser

2021-08-31  04:52 PM                24 $foo
               1 File(s)             24 bytes
               0 Dir(s)  49,260,376,064 bytes free

C:\Users\rpresser>type $foo
this is a dollar file

C:\Users\rpresser>attrib $foo
A                    C:\Users\rpresser\$foo

C:\Users\rpresser>mkdir $bar

C:\Users\rpresser>dir *bar*
 Volume in drive C is OSDisk
 Volume Serial Number is 0263-7E64

 Directory of C:\Users\rpresser

2021-08-31  04:53 PM    <DIR>          $bar
               0 File(s)              0 bytes
               1 Dir(s)  49,260,335,104 bytes free

C:\Users\rpresser>

Note that this was done in a cmd.exe session. If you do it in PowerShell you will have trouble, because $foo will be interpreted as a variable reference.

Answer 2

The $ sign indicates that the folder is hidden. See here for more information.