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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.

thecomputerguru
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    You can run only external commands with sudo, so you need to invoke bash to perform the cd command, using sudo bash -c cd .... – AFH Oct 20 '19 at 15:24
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    I know, that's what I read on this superuser post https://superuser.com/questions/241129/why-wont-sudo-cd-work. – thecomputerguru Oct 20 '19 at 15:51
  • My question is how can I use the cd command with superuser privileges, since sudo doesn't work. – thecomputerguru Oct 20 '19 at 15:53
  • Sorry, misread your question: I was thinking of the mkdir command. Silly mistake. – AFH Oct 20 '19 at 17:01
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    FWIW POSIX says that cd ought to be available as an external command. Questionable value? Sure, but that's the spec. – kojiro Oct 21 '19 at 00:09
  • The 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 Oct 21 '19 at 03:22
  • You can become root with sudo -i. – kevinSpaceyIsKeyserSöze Oct 21 '19 at 10:08
  • Assume you could do sudo cd /foo/bar. It might happen that after that you cannot even cd .. – Hagen von Eitzen Oct 21 '19 at 14:47
  • If 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 Oct 22 '19 at 02:00
  • 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 Oct 22 '19 at 06:25

3 Answers3

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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
u1686_grawity
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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?

Slartibartfast
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  • Sounds like you're talking about relying on each admin's .bash_history instead of using something more reliable like etckeeper? – u1686_grawity Oct 21 '19 at 08:17
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    The 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 Oct 21 '19 at 11:05
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    @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 Oct 21 '19 at 23:29
  • @grawity: I was referring to the system security logs, where sudo typically logs commands issued, including time, user, current working directory, etc. – Slartibartfast Oct 22 '19 at 03:15
  • @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 Oct 22 '19 at 07:19
  • An alias for sudoedit is sudo -e, it saves 1 keypress – Ferrybig Oct 22 '19 at 07:42
  • @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 Oct 23 '19 at 01:39
  • I don't have the folder /root/private so what do I do? – Raul Chiarella May 12 '23 at 18:45
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The fastest way to do what I needed to do was this: 

sudo -s

As described in this answer.

orangecaterpillar
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