Well, what exactly are you trying to do?  Even if you could do 'sudo cd 
directory', simply executing that command will result in NOTHING 
HAPPENING with respect to your next command.  Lets dig in to it at the 
end of the message, but for now trust me.

Oh, and the shortest answer, the conclusion/solution, is at the end, so 
if your eyes start to glaze over as you read the below, jump to the bottom.

First, see what the permissions on <path> is/are.  Try 'ls -ld <path>'.  
If you get Permission denied, and path includes '/', then somewhere 
along the path (ha) your permissions don't let you do a directory 
listing.  If you see something like this:


drwxrwxrw- 6 rusty rusty 4096 Dec 19 16:22 <path>


and you are not rusty nor in group rusty, then you can't do a directory 
listing of <path>


(That (missing!) 'x' there is the key to your (not) being able to see 
the contents.  It enables 'search' for directories, which is what you 
need to be able to see in to, or cd into, the directory)


If any directory on the <path> does not have x set for you, then you 
can't see in to it and get permission denied.


Now, why are both 'sudo cd foo' and 'sudo chdir foo' totally useless?  
(even if you COULD do it!  Which you can't!  See below the below for 
news about 'chdir')


Well, when you type 'sudo' and are successful (to perhaps muddy the 
water a bit - which is to say you have permission to run a command as 
root using sudo), the shell starts a NEW shell, running as root, which 
executes your command and then, when that command completes exits back 
to the shell which started it.  So, let's say your shell's PID is 123.  
You type sudo cd foo, the shell starts a NEW shell,say PID 321, which 
does the cd and then exits back to the shell that started it, PID 123. 
Where the 'current working directory is still wherever you were before 
you typed 'cd'!

A lot of typing and process running to do absolutely nothing!


However, 'chdir' is not a command at all.  Try it:

=== shell interaction begins

Tue Dec 20 23:19:09 RustyC ~/class $ chdir foo

Command 'chdir' not found, did you mean:

   command 'hdir' from deb hfsutils (3.2.6-14)
   command 'cdir' from deb cdtool (2.1.8-release-7)

Try: sudo apt install <deb name>

Tue Dec 20 23:19:35 RustyC ~/class $

=== shell interaction ends

(cdtool has a 'cdir', but it 'lists information about the currently 
loaded audio compact disc', doing nothing w.r.t. current working dir)

Nope, all you get is 'cd', which as they say, is a shell builtin.  Now, 
WHY is it a shell builtin?  Because your 'current working directory' is 
*set* and *maintained* by the shell. Changing directory inside a program 
will not affect the 'current working directory' of the shell that 
started the program (unless there happens to be a hook in bash you can 
call from your program, which is possible, I suppose, but I've never 
heard of it.  And, no chdir(2) does not, I believe, affect the shell 
which started the process which called chdir).


Now, let's keep beating this dead horse, shall we?


Back to the original question, and the meta-question above it, which is 
sort of 'how should I debug this sort of thing?'

The first huge hint is 'permission denied'.  This means that the user 
executing the command does not have (file system) permission to do 
whatever it is they tried to do (I'm speaking here of when a command is 
doing something w.r.t. a file.  Doing 'sudo ' and getting 'Permission 
denied' does not have anything (really) to do with file permissions, so 
isn't involved here).

So, how do you debug this?  The first thing you should do is a long 
directory listing of the file that complained (always use 'ls -ld' for 
this).  If that gets permission denied, then remove the last 'thing' in 
the path and re-do the ls -ld.  Inspect the permissions (the rwxrwxrwx 
things) and the owner/group.  If you are the owner, then look at the 
first 3 permission bits.  If you are NOT the owner, but you are IN the 
group, look at the next 3. If  you are neither the owner nor IN the 
group that owns the file, then look at the last 3. To change in to a 
directory you need execute permissions (you can, in fact, 'cd' into a 
directory that you do not have read permissions to!  But, of course, you 
can't see anything in it!  Try it. 'mkdir foo;chmod 100 foo;cd foo;ls -l').


So, after much ado, we have finally come to the conclusion that some 
directory in 'path' does not have the 'x' permission for you set.

Fix that, you be good.

Rusty (yes, I do sometimes teach a class on Linux, why do you ask? ;-)

On 12/20/22 18:27, Keith Smith via PLUG-discuss wrote:
>
>
> Hi,
>
> Not sure what is going on here:
>
> cd <path> results in message "-bash: cd: <path> : Permission denied".
>
> Then I add sudo : sudo  cd <path> results in message  : "sudo: cd: 
> command not found".
>
> Any help is much appreciated!!
>
> Keith
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