/usr/bin/env: ‘python3\r’: No such file or directory [duplicate]

I'm trying to make my .py files executable so I can run them using ./filename.py, but its not working for me.

What I did was adding the shebang #!/usr/bin python3 and used the command chmod +x filename.py. When I run ./filename.py then as normal user, I get the error message below

bash: ./filename.py: /usr/bin: bad interpreter: Permission denied

As superuser, it tells me this instead:

sudo: unable to execute ./filename.py: Permission denied

Opening the file the usual method (python3 filename.py) it works fine.

When I changed the shebang to #!/usr/bin/env python3 it tells me this:

/usr/bin/env: ‘python3\r’: No such file or directory

1 Answer

The problem are your line ending characters. Your file was created or edited on a Windows system and uses Windows/DOS-style line endings (CR+LF), whereas Linux systems like Ubuntu require Unix-style line endings (LF).

There is a simple tool that can convert the two different styles for you called dos2unix.

Install it by running

sudo apt install dos2unix

After that, you can convert files in either direction using one of the commands

dos2unix /PATH/TO/YOUR/WINDOWS_FILE
unix2dos /PATH/TO/YOUR/LINUX_FILE

Example:

$ cat test.py
#!/usr/bin/env python3
print("ok")
$ ./test.py
/usr/bin/env: ‘python3\r’: No such file or directory
$ dos2unix test.py
dos2unix: converting file test.py to Unix format ...
$ ./test.py
ok

To also come back to what you tried first, the shebang line

#!/usr/bin python3

is of course wrong. It tries to execute the file /usr/bin with python3 and the filename of your script as arguments. This must obviously fail because /usr/bin is a directory and no executable file.