We Keep Coding

running a python program in the command line without "./"

Let's say I have a program called "hello". It is a python script and I want to run it at the linux command line.
I've been able to remove the .py extension as well as the interpreter.
Now when I run it it is [user..path] $ ./hello
it works, but how do I remove the "./". I've already applied the chmod a+x argument to the file and a shebang line at the front of my script.
Basically, I am asking how to run the script as $ hello

Add . to the end of your $PATH variable.
PATH=$PATH:.
Then it will search the current directory when looking for programs to run.
Note that you should not generally put . at the beginning of $PATH. If you cd into someone else's directory, and they have a program that's the same name as a system program (e.g. ls), you'll execute their version instead of the real one.
You could also create your own directory where you install programs, and put that directory in $PATH.
PATH=~/bin:$PATH
Now you copy hello to your ~/bin directory and run hello.

How is git able to run C scripts in the current directory as a command on terminal?

I have been looking into bash and shell recently and been trying to work out how git is able to make a terminal command that runs C scripts in the current directory e.g git init, git push/pull etc.
I have been trying to simulate it in python, by making an executable python script in my home directory,
#!/usr/bin/env python
import os
print("current_dir: ",os.getcwd()) #prints /Users/usr/folder/script.py
Then I create a .command file that calls the python script
cd
cd FOLDER/
python3 SCRIPT.py
and editing the bash profile to export a variable to run the .command file.
export mycommand=/Users/urn/folder/command.command
Although this is not even nearly close to the way git achieves its command line. For example, when I run my script is not actually a terminal command it is just an environment variable, hence the $.
$mycommand
Secondly, this goes to the directory of the python file and runs the script from with that directory, therefore the output will always be the same
/Users/usr/folder/script.py
Although in git it runs the file in the current directory. Therefore the print statement would change depending on the terminal directory.
How am I able to create my own 'terminal command' such as git init to run my python script in whatever directory I'm in. Ps, I'm on mac.
Any help would be greatly appreciated :)

It sounds like you are missing at least two basic concepts:
The search path: when you issue a command that is not a shell function or built-in and that has an unqualified name (one with no / characters), the shell searches a list of zero or more directories for a matching executable file. This list of directories is the "path", and it is stored in the PATH environment variable. You can change it if you wish. This is how the shell finds the git program when you do not specify a path to it.
Executable scripts: Python, shell, Perl, etc. programs that must be run via an interpreter can be made executable by name alone by including an appropriate shebang line as the very first line and assigning an executable mode. You include an appropriate shebang line in your example Python program, in fact, but you seem not to understand its significance, because you explicitly launch the script via the python3 command. The shebang line is just another comment to Python, but it is meaningful to the system.
It seems like you probably also are missing some other concepts, like the fact that your script doesn't need to be in the current working directory for you to run it via the python3 launcher, path notwithstanding. Just specify its full pathname. Alternatively, Python has its own variation on a path, PYTHONPATH, by which it can locate modules and packages. These are alternatives, however -- the first two points are enough to achieve your apparent objective. Specifically,
Keep the shebang line in your script, though your default python is probably v2.7, so if you really want to run it specifically via python3 then modify the shebang line to say so:
#!/usr/bin/env python3
Make sure the file has executable mode. For example,
chmod 0755 /Users/urn/bin/SCRIPT.py
Then you should be able to execute the script from anywhere via its full pathname.
To access it from anywhere via its simple name, ensure that the directory containing it is in your path. For this purpose, it would be wise to choose an appropriate directory, such as /usr/local/bin or /Users/urn/bin (you may need to create the directory first). Whichever you choose, ensure that that directory is in your PATH. For example, edit /Users/urn/.bash_profile, creating it if necessary, and ensure that it contains (say) the commands
PATH=$PATH:/Users/urn/bin
export PATH
That will take effect in new Terminal windows you open afterward, but not automatically in any that are already open. In those windows, you will be able to run the script, from anywhere, via its simple name.

Why does python script with execute permission not run on Ubuntu?

I have a script/app/program written in python 3. I uploaded it to my Ubuntu box and changed the permission to allow execution by all. I am able to run python myapp.py with no problem but I cannot run myapp.py. I get an error that it is not a recognized command. I have at the top
#!/usr/bin/env python3
That should be right from all that I've read so far. I even tried
#!/usr/bin/python3
in the program referred to as myapp.py
Neither of them work.
I was following an online course and all was going well until we got to that point of running python scripts like regular programs by setting the execute setting.

If you are talking about, executing it from any directory, you need to do two things.
Setting the path variable. Lets say I need to execute Test.py, which is in Desktop, from any directory
export PATH=$PATH:/home/thefourtheye/Desktop/
Giving execute permission to the file
chmod 755 /home/thefourtheye/Desktop/Test.py
Then I can execute it by simply typing Test.py.

You cannot execute file in unix by name without directory name due to some security considerations, so you have to add . as directory (it will look like ./myapp.py)

. isn't on your path (and it probably shouldn't be for security reasons), so Ubuntu won't look in the current directory for a myapp.py program to run. You need to explicitly specify ./myapp.py to indicate that you want to run the myapp.py file in the current directory.

You should either call it as
./myapp.py
or the current directory should be in the PATH environment variable (either as full directory path name or as '.' which indicates the dynamic current path), check with
echo $PATH
to add it you can run
export PATH=$PATH:.

If you want to run it like:
user#machine:~$ myapp.py
You must put the script in the /usr/bin/ or /bin/ or something similar. In other case you must run like:
user#machine:~/appFolder/$ ./myapp.py

did you try:
$ sudo chmod a+x myapp.py
then run the python code using:
$ ./myapp.py

For linux users, may be text format dos/unix problem!
try,
sudo dos2unix name_of_your_script
then shebangs will probably get to work properly! That was what happened to me.
PS:
Ofcourse, also your script has to be executable
(sudo chmod +x name_of_your_script )

How to run python script on terminal (ubuntu)?

I'm new with python, I've been learning for a few weeks. However now I've just changed my OS and I'm now using ubuntu and I can't run any script on my terminal.
I made sure to have the #!/usr/bin/env python
but when I go to the terminal and type, for example python test.py
the terminal shows an error message like this
python: can't open file 'test.py': [Errno 2] No such file or directory
what do I do?
I must save the file in any specific folder to make it run on terminal?

This error:
python: can't open file 'test.py': [Errno 2] No such file or directory
Means that the file "test.py" doesn't exist. (Or, it does, but it isn't in the current working directory.)
I must save the file in any specific folder to make it run on terminal?
No, it can be where ever you want. However, if you just say, "test.py", you'll need to be in the directory containing test.py.
Your terminal (actually, the shell in the terminal) has a concept of "Current working directory", which is what directory (folder) it is currently "in".
Thus, if you type something like:
python test.py
test.py needs to be in the current working directory. In Linux, you can change the current working directory with cd. You might want a tutorial if you're new. (Note that the first hit on that search for me is this YouTube video. The author in the video is using a Mac, but both Mac and Linux use bash for a shell, so it should apply to you.)

Set the PATH as below:
In the csh shell − type setenv PATH "$PATH:/usr/local/bin/python" and press Enter.
In the bash shell (Linux) − type export PATH="$PATH:/usr/local/bin/python" and press Enter.
In the sh or ksh shell − type PATH="$PATH:/usr/local/bin/python" and press Enter.
Note − /usr/local/bin/python is the path of the Python directory
now run as below:
-bash-4.2$ python test.py
Hello, Python!

Save your python file in a spot where you will be able to find it again. Then navigate to that spot using the command line (cd /home/[profile]/spot/you/saved/file) or go to that location with the file browser. If you use the latter, right click and select "Open In Terminal." When the terminal opens, type "sudo chmod +x Yourfilename." After entering your password, type "python ./Yourfilename" which will open your python file in the command line. Hope this helps!
Running Linux Mint

Sorry, Im a newbie myself and I had this issue:
./hello.py: line 1: syntax error near unexpected token "Hello World"'
./hello.py: line 1:print("Hello World")'
I added the file header for the python 'deal' as #!/usr/bin/python
Then simple executed the program with './hello.py'

First create the file you want, with any editor like vi or gedit. And save with a .py extension. In that the first line should be
#!/usr/bin/env python

script file not found when using cmd.exe

I'm just getting started with Python and am trying to run a program from the command line, as it is done on this website under the heading "Python Program". So I made script hello.py, it's located in my computer at C:\Python27.
In the example, they run the script by typing python hello.py Guido. When I try to do this, it doesn't work. Firstly, I'm not entirely sure what is meant by the 'command line', but I'm using cmd.exe in Windows XP. I get this:
python: can't open file 'hello.py': [Errno 2] No such file or directory.
I have already specified PATH as C:\Python27.
Also, when I try to run the program from the Python shell by typing hello.py Guido I get
SyntaxError: invalid syntax.

When you start cmd.exe, the default directory is your Documents and Settings: since your file hello.py is not there, the python interpreter can't find it, thus giving you the [Errno 2] No such file or directory error. To solve that, just change your current working directory:
C:\Documents...>cd C:\Python27
C:\Python27> python hello.py Guido
Anyway, it is a good approach not to having your files inside the python directory (create a directory in your documents for python sources and use the same approach).
When you are running the python shell, you cannot explicitly call python files, so in your case it tries to run hello.py as a command (which doesn't exists) and it gives you a syntax error.

You need to locate your cmd current directory at C:\Python27:
cd C:\Python27
because the path python loads is relative. You can also use a full path:
python C:\Python2.7\hello.py

Try without "python", when you put python directory in path, it automatically connects ".py" extension with python, so there is no need in writing "python hello.py Guido"
Just go to directory where .py is located, and call "hello.py"

What's your current working directory and where is hello.py located? To execute that command, hello.py should be in the same directory from where you started the commend line (cmd.exe). Otherwise you need to the write the absolute path of hello.py (like python C:.....\hello.py Guido) instead of just the filename 'hello.py'.

I had also this problem but because of ether reason: I accidently added spaces to the names of some of the file's names, so the CMD didn't recognized the names.
for example: 'run .bat'