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I put "exit" in my .bashrc file. I don't have physical access to the machine so to connect to it I use ssh. I don't have root privileges. Every time I connect to the server, the connection automatically closes.

So far, I've tried:

  • Overwriting .bashrc with scp and sftp. The connection closes before I can do anything.
  • Using a few different GUI programs to access ssh (connection closes)
  • Overwriting the file with ftp. (can't use ftp)
  • From my home computer
    • $ ssh host "bash --noprofile --norc" (connection closes)
    • $ ssh host "mv .bashrc bashrc_temp" (connection closes)
    • $ ssh host "rm .bashrc" (same thing)
    • $ ssh host -t (connection closes)

Is there anything I can do to disable .bashrc or maybe overwrite the file before .bashrc is sourced?

UPDATE

@ring0

I tried your suggestion, but no luck. The bashrc file still runs first.

Another thing I tried was logging in with another account and sudo editing the .bashrc, but I don't have sudo privileges on this account.

I guess I'll contact the admin.

EDIT

@shellholic

I can't believe it, but this approach worked! Even though "exit" occurs within the first few lines (composed only of a few if blocks and export statements) in the .bashrc file, I still managed to Ctrl-c interrupt it successfully within twenty tries (took about 3 minutes). I removed the offending line in the .bashrc and everything is in working order again.

splattne
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camel_space
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    http://www.darwinawards.com/ you should have (temporary) an access as a user who can overwrite your .bashrc file, or change your default shell to something else. "Ask your system Administrator" as MS says. –  Nov 27 '10 at 09:05
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    `man 8 sshd` says that it `9. Runs user's shell or command.` as the ninth step... :-/ –  Nov 27 '10 at 09:17
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    scp will also stop working because the shell still gets opened and .bashrc gets called – Aleksandr Levchuk Nov 28 '10 at 02:51
  • FYI the reason most of these suggestions do not work is because ssh executes any command by by passing it as an argument to the user's shell. Search for execve in session.c. There is no way to modify/add/delete the arguments of this invocation of the user's shell. – Mark Wagner May 11 '18 at 17:18

10 Answers10

41

you can try to abort (ctrl+C) before the exit part of your .bashrc is executed.

I tried by adding the following at the top of a testuser's bashrc, it works, it's just a matter of timing. Very easy in my case:

sleep 3
echo "Too late... bye"
exit 0
shellholic
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    +1, because it's probably the only solution that doesn't require help from the system administrator. However, a lot of luck is required to have correct timing (ssh -v host might help a bit). – JooMing Nov 27 '10 at 20:38
  • Actually the ctrl+C did work. Even without the sleep. I placed "exit" into my bashrc and was able to recover with a quick ctrl+C after about 4 tries. Please make some edit the answer so I can change the "-1" to "+1". – Aleksandr Levchuk Nov 28 '10 at 02:49
  • @Aleksandr Levchuk done – shellholic Nov 28 '10 at 02:54
  • Unbelievable, this works! – dcai Dec 01 '12 at 12:52
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    I very much appreciate the combination of pathetically ridiculous low-tech and brutal effectiveness here. – unixtippse Jun 11 '13 at 16:06
  • @shellholic Thank you again for your solution! Saved me after I accidentally overwrote my bashrc file. Now I am not locked out and can log in, but how do I restore the default contents of bashrc? I'm running CentOS 6.5 – Nickolai Leschov Apr 05 '14 at 16:19
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    I'm laughing like crazy, that rush when it finally works. Thanks @JooMing, I tried all methods from here https://serverfault.com/questions/94503/login-without-running-bash-profile-or-bashrc even the one with pressing Ctrl+C, but it only worked after adding the -v option! – mxmlnkn Oct 12 '17 at 20:02
  • This worked for me too with a VM that had no other admin user, so no other way to save it – ytoledano Mar 22 '18 at 15:39
  • awesome ! Is there a way you can script this such that `Ctrl+c` is sent as soon as the connection is opened? I'm thinking about somehow piping the `ctrl+c` into the SSH – Ciprian Tomoiagă Nov 14 '18 at 13:04
15

I managed to mess up my .bashrc file too on a new cluster I've been given trial access to. Not wanting to seem like a noob, the last thing I wanted to do was ask for help from the admins, and I couldn't get a well-timed ^+C to work.
What did work however, was to send an 'rm' command as a final argument to ssh. i.e.

ssh -tv user@host rm .bashrc

I couldn't get a 'mv' command to work (tried before without -t), so I think the -t option must have done it, but you can test that if you want. I've now recovered from the .bashrc~ file (made by vim) everything but the dodgy line in question and everything is right in the world! =D

Alex Leach
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3

If you can log in as a different user, try this:

su user -s /bin/sh

You'll need your password, of course.

Cakemox
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3

If I recall some bad experiences I have had like this, the ssh, scp, sftp do seem to run the initialization files.

My suggestion is to use simple FTP and then delete or rename file bad file on the FTP command line after logging in. I'm assumming that your system will allow you FTP access. In such a case, be sure to change your password (securely) when you have finished repair.

mdpc
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  • Filezilla worked perfectly for this. Just have to drop-down "Server" menu and select "Force show hidden files" setting. – Danny G Aug 31 '15 at 01:57
2

From man ssh (for OpenSSH_5.6p1 at least, not sure when it was added),

~/.ssh/rc
        Commands in this file are executed by ssh when the user logs in, just
        before the user's shell (or command) is started.  See the sshd(8) manual
        page for more information.

..which means you can create ~/.ssh/rc containing the following:

mv ~/.bashrc ~/bak.bashrc

Then when you ssh in, the problematic bashrc will be moved out the way, before your login shell is started - you can then obviously fix the bak.bashrc and move it back into place

dbr
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1

A couple of suggestions that worked for me from this Reddit thread:

ssh you@the.box /bin/bash --noprofile --norc
ssh -t jacksgt@example.com vi ./.bashrc
abalter
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0

Connect via SCP or SFTP and edit/rename/delete your .bashrc file that way. Edit - D'oh, I see you said you tried that. Oh well.

mfinni
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0

I've had the same problem, and somehow was able to solve it. I used ssh to access the system, and pressed and held Ctrl+c as soon as I logged into the system. Then, ~/.bashrc was not read, and I was able to modify it.

miyashin
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0
  1. Interrupt grub bootloader by pressing e ... again press e to enter grub loading lines, again press e to edit the kernel line,
  2. go to end of line;
  3. add init=/bin/bash at the end of line, 1 .enter to return, b to boot,
  4. it will open a bash shell,
  5. open vim /root/.bashrc and edit accordingly.

exit and now you will be able to login

Pablo A
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Haseeb
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0

If you're using Homestead Vagrant...

Here is how I got myself out of this pickle.

(Using Git Bash on Windows 10)

cd ../Homestead/
mv ~/.ssh/known_hosts ~/.ssh/known_hosts_OLD
ssh vagrant@127.0.0.1 -p 2222 mv ./.bashrc ./.bashrc_OLD

Note: the default password is "vagrant"

These articles helped me:

Nisse Engström
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Ryan
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