35

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
  • 28,776
camel_space
  • 493

12 Answers12

46

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
  • 1,365
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
  • 1,787
4

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
  • 11,914
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
  • 26,021
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
  • 1,588
2

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
  • 131
0

I wrote a Python script to automate the ctrl+c thing because I really cannot success using bare hands...

import pyautogui
import time

def countdown(seconds):
    print("Counting down before moving your mouse to the terminal:", end=" ")
    for i in range(seconds, 0, -1):
        print(i, end=" ")
        time.sleep(1)
    print("Script starts!")


def clear():
    pyautogui.typewrite("clear")
    pyautogui.press("enter")


def stop():
    pyautogui.hotkey("ctrl", "c")


pyautogui.FAILSAFE = True
countdown(5)
total_retry = 1
sleep_ms = 230
host = None  # could be "user@host" or "ssh_host" defined in ~/.ssh/config
for i in range(total_retry):
    stop()
    pyautogui.click()
    clear()
    pyautogui.typewrite(f"ssh -v {host}")
    pyautogui.press("enter")
    time.sleep(sleep_ms / 1000)
    for i in range(5):
        stop()

All you need to do is:

  1. Change the host variable to yours
  2. Run the script and move your mouse to the terminal in 5 seconds (as written in countdown)
  3. The script will try to ssh to your host and then press ctrl+c after sleep_ms milliseconds
  4. Run this script for several times to adjust the sleep_ms variable that may stop early or late (in my case, it's 230ms). You can manually do binary search for this empirical value
  5. Once you find a proper sleep_ms, change total_retry to any number (e.g. 100) to start automating this
  6. It may take dozens of times to finally work (at least for myself, but I believe it will finally succeed in only a few minutes tops), and once it works, stop the script (don't worry about the side effect of running this script in your remote machine, because it will simply fail repeatly and won't change anything in your remote machine)

NOTE: Don't forget to enable the accessibility for your code editor (e.g., VSCode) if you are using MacOS.

Shunchi Zhang
  • 1
0

If you can log in as another user, you can switch to root(or user you want) without triggering any profile or rc files by running:

su root -c "bash --noprofile --norc"
Minor Project
  • 1
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
  • 36,892
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
  • 731
  • 5
  • 2
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
  • 210
Haseeb
  • 11
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
  • 210
Ryan
  • 109