I am trying to get rid of this folder, but the result is saying that fish expects a variable name after this $. What does it mean ? And how do i get rid of this folder ?

No, it should be:

↹↹↹This↹↹↹

What does ls show?

you can escape special charcters with \ something like \'folder\'\$\'\\003\' might work

be careful with rm -rf as you might delete your entire disk if done badly. use some other command to test if it targets the correct directory like ls \'folder\'\$\'\\003\'

Yep as others have noted put a \ in front of each special character. The \ tells the system to treat the following character as a alphanumeric character in the string and not as a operator or a command. Since ', $ and \ are all special characters you will need a \ just before each when typing this name. Also as mentioned do this with a benign command like ls first to make sure your only acting on that specific directory or you might have a bad day.

Edit: How the heck did you get some of those folder names? Looks like a script with incorrect variable/macro substitution made these.

‘folder’$‘\003’

Oh that is unpleasantly fiddly to insert all the backslashes to escape the bits. Testing here, (fiddly to even make a dir called that, lol), for fun, instead of just pressing tab, ... is it just the $ and the \ you need to escape? and the ' are fine? Results here are inconclusive, not sure I managed to make a file with the same name, it showing here with extra outer '.

Probably easier to just interactively.... but yeah, in case needing to have it written for a script... probably easiest still to just press tab, to see how it arranges the escape syntax, and paste that into your script. ;)

The fi in fish is friendly interactive, after all.

I believe u should Type

rm -r \'folder\'\$\'\\003\'

Basically a \ interprets the following character as a character. With the ' I’m not sure, so maybe

rm -r 'folder'\$'\\003'

could do the trick too

Edit: correct code

Are the hyphens apostrophes and the backslash part of the folder name too?

If so, try \'folder\'\$\'\\003\' escaping the hyphens apostrophes ', the dollar sign $ and the backslash \.

The default output itself is pretty definitive, assuming you are indeed using GNU ls and don't have the QUOTING_STYLE environment variable set. https://www.gnu.org/software/coreutils/manual/html_node/Formatting-the-file-names.html explains all this (including your options) and more.

$ touch $'folder\x03'
$ ls --quoting-style shell-escape  # the default
'folder'$'\003'
$ ls --quoting-style c
"folder\003"
$ ls --quoting-style escape
folder\003