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Why do people write the #!/usr/bin/env python shebang on the first line of a Python script?


Why do people write the #!/usr/bin/env python shebang on the first line of a Python script?

By : Luka Krulanovic
Date : October 28 2020, 08:00 PM
hope this fix your issue If you have several versions of Python installed, /usr/bin/env will ensure the interpreter used is the first one on your environment's $PATH. The alternative would be to hardcode something like #!/usr/bin/python; that's ok, but less flexible.
In Unix, an executable file that's meant to be interpreted can indicate what interpreter to use by having a #! at the start of the first line, followed by the interpreter (and any flags it may need).
code :


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Add Python arguments in script's shebang line (script made with buildout and zc.recipe.egg:scripts)

Add Python arguments in script's shebang line (script made with buildout and zc.recipe.egg:scripts)


By : user2883492
Date : March 29 2020, 07:55 AM
fixed the issue. Will look into that further You can force unbuffered I/O from within your Python script by re-opening stdin or stdout by opening a new file object on the filenumber:
code :
import io, os, sys
try:
    # Python 3, open as binary, then wrap in a TextIOWrapper
    unbuffered = io.TextIOWrapper(open(sys.stdout.fileno(), 'wb', 0), write_through=True)
except TypeError:
    # Python 2
    unbuffered = os.fdopen(sys.stdout.fileno(), 'w', 0)
sys.stdout = unbuffered
Python script: problems with shebang line (unix)

Python script: problems with shebang line (unix)


By : Himal Poudel
Date : March 29 2020, 07:55 AM
Does that help Bash shebangs expect an absolute path to the interpreter. So in your case you need to specify the full path to your Python interpreter i.e.:
code :
#!/Users/me/Documents/Python/todo-api/flask/bin
Permission denied running python script with the shebang line in linux

Permission denied running python script with the shebang line in linux


By : Elyssa Shoemaker
Date : March 29 2020, 07:55 AM
I hope this helps you . Make sure to use LF line endings not CRLF line endings when running on linux! Thank you @jwodder for the suggestion.
I was using sublimetext to edit my files in windows and running the files on the linux machines. I changed the preferences in sublime to use unix line endings (LF) but I already wrote the file in the DOS endings (CRLF). I thought it would switch over the line endings for me. My assumption was wrong. I converted them all to LF and the script ran as expected.
interchangeable shebang line in Python script for dual OSes?

interchangeable shebang line in Python script for dual OSes?


By : Aji Wahyu
Date : March 29 2020, 07:55 AM
around this issue If you don't mind adding extra steps, ou can create a launcher script launcher.py like:
code :
#!/usr/bin/env python

import subprocess
import sys

if __name__ != "__main__":
    print("This is a launcher. Please run only as a main script.")
    exit(-1)

INTERPRETERS = {
    "win": r"C:\Users\windows-username\Envs\some_env\Scripts\python.exe",  # Windows
    "darwin": "/Users/os-x-username/.virtualenvs/some_env/bin/python",  # OSX
    "linux": "/home/linux-user/.virtualenvs/some_env/bin/python"  # Linux
    # etc.
}

TARGET_SCRIPT = "original_script_name.py"

interpreter = None
for i in INTERPRETERS:  # let's find a suitable interpreter for the current platform
    if sys.platform.startswith(i):
        interpreter = i
        break
if not interpreter:
    print("No suitable interpreter found for platform:", sys.platform)
    exit(-1)

main_proc = subprocess.Popen([interpreter, TARGET_SCRIPT] + sys.argv[1:])  # call virtualenv
main_proc.communicate()  # wait for it to finish

exit(main_proc.poll())  # redirect the return code
Python: How to write the output of python script to a file in the same line separated by tab

Python: How to write the output of python script to a file in the same line separated by tab


By : RayKwok
Date : March 29 2020, 07:55 AM
this one helps. First it should be noted that file.write() does not add any newline characters implicitly, and those line feeds you get are passed somehow within the argument supplied to that function.
Unfortunately it is not clear from the example how the written keys and values are obtained. However note that the title lines (for example, the one with FirstTitle) contain an indent before the title itself, probably a tab character. From that I would suppose that the values in d dictionary are some strings that end with a newline character.
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