9
2
Is there a way to run the cd
command with superuser privileges to gain access to directories that are owned by root? When I run sudo cd <path>
, I get sudo: cd: command not found
.
9
2
Is there a way to run the cd
command with superuser privileges to gain access to directories that are owned by root? When I run sudo cd <path>
, I get sudo: cd: command not found
.
22
The other answer isn't wrong.
Possibly a better answer is:
The sudo tool is intended to take actions as a superuser, and you're describing something that is more of a state change that would precede actions such as 'ls' or 'vi' or others to make them simpler.
I suggest, e.g. if you wanted to edit a file in /root/private/:
sudo ls /root
sudo ls /root/private
sudoedit /root/private/<name from previous ls command>
This is definitely more typing, and a little harder than just changing directories. However, it is far more audit-able, and much more in-line with the principles behind sudo than running some variant of 'sudo bash.'
If you are working in a secure environment, your IA team will thank you. If you find yourself wondering: "What change did I make the other day?," then you will thank you, because you won't have to wonder what file or files you edited.
All of this said, enabling and executing some form of 'sudo bash' is definitely easier. If you were looking for easier, why are you using 'sudo' in the first place instead of just logging in as root?
Sounds like you're talking about relying on each admin's .bash_history instead of using something more reliable like etckeeper? – user1686 – 2019-10-21T08:17:26.217
5The hideously annoying thing in this is that tab-completion of the filename in the last command doesn't work if the non-root user doesn't have read access to the directory. So you have to copy paste or hand-type. I wonder if anyone would have created a sudo
-using completion script for Bash. – ilkkachu – 2019-10-21T11:05:54.910
1@ilkkachu: At that point I usually just sudo -s
to start a root shell on personal-use systems (so auditing isn't a huge deal). I don't want automatically-generated commands running under sudo. (Cluttering logs at best, at worst exposing some hackily-written completion code to malicious filenames with spaces and worse in them.) – Peter Cordes – 2019-10-21T23:29:02.640
@grawity: I was referring to the system security logs, where sudo typically logs commands issued, including time, user, current working directory, etc. – Slartibartfast – 2019-10-22T03:15:19.507
@PeterCordes, yep. I'd be tempted to just chmod +r
or raise the question if a custom should be made where some staff
group has read permissions to root owned directories, because tab-completion is useful. Yes, the completion code would need to be carefully written (and I think I've seen some not work with funny filenames), but I don't think the clutter should be an issue since you can just grep
out any ls
commands which don't do anything, and which people will need to run under sudo
anyway if they don't have read permissions as their regular UID. – ilkkachu – 2019-10-22T07:19:51.447
An alias for sudoedit
is sudo -e
, it saves 1 keypress – Ferrybig – 2019-10-22T07:42:34.203
@ferrybig: Fair point, but it means I move my fingers two rows below, and two rows above home row, whereas 'edit' (not to mention 'sudoedit') is a word that I touch-type without thinking. I might save one keypress and increase time and typos significantly. – Slartibartfast – 2019-10-23T01:39:43.823
23
As you noted, cd
is a shell built-in command, and there's a reason for that: the "current directory" is a per-process parameter which can be only changed by the process itself.
Your shell's working directory cannot be changed by any child process – so even if you manage to run cd
in a privileged subshell, it'll only change the working directory of that temporary subshell, and it does not matter what method of raising privileges you use.
So for sudo cd
to work, sudo itself would have to be a shell built-in, and it would need some way to raise privileges of an already-running process. Currently no such mechanism exists on Linux (nor most other operating systems).
One way to achieve what you want is to run an interactive shell with root privileges (any method works), and just use the regular cd
in it:
[user@host /]$ sudo bash
[root@host /]# cd /root/secret
If you want to do it all in one command, it would have to look like this – first change the working directory, then start an interactive shell:
sudo bash -c "cd /root/secret && bash"
su -c "cd /root/secret && zsh"
Note: The outer command doesn't have to be a shell, it just needs to be something that changes its working directory and executes a new command. Recent Linux systems have one or two helpers which could be used:
sudo nsenter --wd="/root/secret" bash # util-linux v2.23 (debian jessie)
sudo env --chdir="/root/secret" bash # coreutils v8.28 (debian buster)
The advantage of this method is that it doesn't require nested quoting; you can run a multi-word command without having troubles with whitespace or special characters.
Finally, some programs have a built-in option to change their working directory:
sudo make -C /etc
sudo git -C /root/secret log
1sudo -s
starts an interactive $SHELL
in the current directory; it's (AFAIK) the canonical way to do sudo bash
– Peter Cordes – 2019-10-22T07:23:58.113
0
-3
Sure, just do this:
sudo $SHELL -c "cd <path>"
The key is the -c
option that runs the commands that are quoted after that -c
.
2When I tried running that, nothing happened. Is there a way to do it in a current bash shell session? – thecomputerguru – 2019-10-20T15:45:44.520
3When I run that command, it runs in a subshell then exits immediately. – thecomputerguru – 2019-10-20T15:58:48.117
3This proposal is of course useless unless you extend it to make it do something useful while there, before simply exiting. Even though that particular issue inherits from the question itself, simply ignoring it makes this a misleading post that will waste reader's time, rather than a useful answer. – Chris Stratton – 2019-10-21T00:51:48.677
1
@ChrisStratton The question is then an “XY Problem” scenario. And perhaps I should have asked for clarification. But many times people — including me — will as a specific question here without really explaining the full need for that issue to be solved. For all I know, the sudo cd [path]
could be sudo cd [path] && [do something] && [and do something else]
. So ultimately your attitude speaks for itself and is unnecessarily chastising.
4@JakeGould no, it could not - because your new example does not work either, for the same reason that the subsequent commands still do not run as root. To demonstrated your misunderstanding try: sudo whoami && whoami
– Chris Stratton – 2019-10-21T02:27:50.317
1While the question certainly is an "XY Problem", this answer should at least point out that the command it contains does nothing, and demonstrate how to turn it into something that does something - crucially, including the correct placement of quotes. – IMSoP – 2019-10-21T09:23:36.647
2You can run only external commands with
sudo
, so you need to invokebash
to perform thecd
command, usingsudo bash -c cd ...
. – AFH – 2019-10-20T15:24:34.8871
I know, that's what I read on this superuser post https://superuser.com/questions/241129/why-wont-sudo-cd-work.
– thecomputerguru – 2019-10-20T15:51:48.760My question is how can I use the
cd
command with superuser privileges, since sudo doesn't work. – thecomputerguru – 2019-10-20T15:53:34.183Sorry, misread your question: I was thinking of the
mkdir
command. Silly mistake. – AFH – 2019-10-20T17:01:51.1302
FWIW POSIX says that cd ought to be available as an external command. Questionable value? Sure, but that's the spec.
– kojiro – 2019-10-21T00:09:14.377The easy way is to log in as root, assuming you're typing the cd command directly, rather than in a macro. (You don't say exactly how you're using it.) – jamesqf – 2019-10-21T03:22:36.100
You can become root with
sudo -i
. – kevinSpaceyIsKeyserSöze – 2019-10-21T10:08:58.740Assume you could do
sudo cd /foo/bar
. It might happen that after that you cannot evencd ..
– Hagen von Eitzen – 2019-10-21T14:47:13.510If you want to play around with the situation you can change as a normal user in a directory and after that use a different root shell to remove the x permission. (A variation of this is chroot with forgetting to cd first) – eckes – 2019-10-22T02:00:55.373
Just about everybody learning to use the CLI (command line interface) makes this mistake sooner or later. It's a natural thing to want to do from a human perspective, but it doesn't make any sense from the shell's perspective. – Joe – 2019-10-22T06:25:27.233