Getting Python errors whenever I try to use terminal in Linux Mint

Question

I've had Mint installed as a dual boot on my laptop for some time. I use it as my dev environment, for desktop and web related coding. I recently started getting errors which have rendered my terminal unusable. As soon as I start the program up I get the error

/usr/bin/env: bash: No such file or directory

Whenever I try to run a command, I then get the following output:

brae@G62-Linux ~ $ ifconfig
Traceback (most recent call last):
File "/usr/lib/command-not-found", line 21, in <module>
os.execvp("python3", [sys.argv[0]] + sys.argv)
File "/usr/lib/python2.7/os.py", line 344, in execvp
_execvpe(file, args)
File "/usr/lib/python2.7/os.py", line 380, in _execvpe
func(fullname, *argrest)
OSError: [Errno 2] No such file or directory

I don't want to start screwing around with files I don't fully understand, and most of the standard things (apt-get update etc.) aren't possible because of the errors. Can anyone give me any advice? I would just blank the partition and reinstall but I really can't be bothered going through all of that if I don't need to.

Thanks very much.

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EDIT- SOLUTION

Thanks to the best answer below, I tracked down the problem to my .bashrc file. Turns out something had modified the file to alter the PATH variable with a Ruby environment which was causing the error. I simply deleted this section from the file (in my case this left the .bashrc file empty) and this solved the error. I believe that if this leaves the file blank, you can also change the .bash_profile (or .profile) file to no longer call the .bashrc file as it is not a requirement for the process.

Thanks for you help everyone who answered, particularly apaul

Answer 1

Many possibilities. At login time, usually, 3 steps are done:

1) At login time, the shell specified in /etc/passwd is launched. So I'd first have a look at /etc/passwd (using GUI as gedit, since you can't use terminal...) and check the shell (it's the last field). You may have a line like this for your user:

user:x:500:500::/home/user:/bin/bash

(You may have /bin/sh, /bin/csh, /bin/zsh, ... but /bin/bash is the most common)

2) Then the shell will read the content of your /home/user/.bash_profile (if you use bash). So I'd look this file (ie: open it with gedit, but watch out, filenames starting with a . are hidden by default) and see if it launch any python command.

3) Finally, /home/user/.bashrc is also read when launching your terminal. So I'd have a look at this file too.

These are the first steps I'd do, looking if any of these files launch a python, ipython, xonsh command, or any py script.