Some programs can be executed from anywhere with a single one-word command. An example of this is youtube-dl, which is a python program that can be executed with the simple command youtube-dl [input]. As far as I have understood, this is simply because there exists a file called /usr/bin/youtube-dl, and /usr/bin is in PATH. However, I do not understand what I have to do to make something like this myself. Right now, I have a python project called testproject that includes a python program like this:
~/testproject/files/myownprogram.py
What do I have to do to make this a binary executable such as youtube-dl?
I know I can make an alias mop="python ~/testproject/files/myownprogram.py", and this is also what I have done, and it works fine. That is, I can write $ mop, and successfully run my program.
But for curiosity's, and learning's, sake, I want to know how to make a file such as the /usr/bin/youtube-dl file, removing the need for aliases.
I find this hard to find information about in search engines...
Any help is greatly appreciated! :-)
Edit:
My question differs from the one marked as duplicate, in that I'm not looking to execute it as a .sh-script. I simply want to execute it as a suffix-less one-word command, similar to all the other executables that are in /usr/bin. :-)
Ex.: $ myown should run my program, without the need for aliases or writing ".sh" or ".py" at the prompt. That is, I want to have a file /usr/bin/myown that somehow runs my testproject at the simple command myownfrom anywhere.
The applications are being executed "from anywhere" because the system has a specific hierarchy of places it looks for these files (the current directory, then the system path). So, it knows to look in /usr/bin because that's in your system path.
As to ensuring it to use python when it's executed, you should add the following to the top of the file (check out some python application source code and you'll see this):
#!/usr/bin/env python
This tells the system to execute the script using the systems "python" command.
Related
I am aware that similar questions have been asked before, but I either don't understand the answers, or there aren't any; so I decided to describe my problem in as much detail as possible.
Problem:
RStudio reticulate package uses Python from this path:
"/usr/bin/python"
but I want it to use python from this path - always, as a default:
"/Library/Frameworks/Python.framework/Versions/3.7/bin/python3"
How do I know it happens?
I open RStudio, and create a new python script. A new file with an extension .py is generated. I type something in:
import pandas as pd
and execute (by clicking cmd+enter). I then see what happens in the console - the reticulate package is called:
reticulate::repl_python()
Python 2.7.10 (/usr/bin/python)
Reticulate 1.12 REPL -- A Python interpreter in R.
I would like to permanently change where the reticulate package looks for Python.
From the Terminal I know:
$ python --version
Python 3.7.3
which python3
/Library/Frameworks/Python.framework/Versions/3.7/bin/python3
So, I would like to tell RStudio to always look in this path to find Python 3.7. I have tried to use the following command, run from an R script:
use_python("/Library/Frameworks/Python.framework/Versions/3.7/bin/python3")
but it doesn't do anything - my naive understanding is that this command is useful within an R markdown file, i.e. when I have code that combines R and Python, in separate chunks. I would like to change the path that is used when a Python script is run from within RStudio. Is there some kind of a config file I could edit?
I hope this makes sense. I am not a regular Python user, only started learning now, and I am also not very good with paths, so I would appreciate step-by-step answers.
OK, so I have posted too early - after some more googling I can solve this problem myself, but I think it is worth posting an answer here for people like me (i.e. not path-proficient or python-proficient).
There is something like a config file for R, called .Renviron. In order to access it, use Terminal to go to your home directory (i.e. the one that you go to when you type 'cd'). If you have never used this file before, it might not exist, in which case you need to create it.
Once in your home directory, type:
ls -a
then check on the list of files that appears whether .Renviron is there. Below are instructions what if you already have .Renviron (IF YES), and what if you don't (IF NO).
IF NO, type:
touch .Renviron
which creates the file.
IF YES, just proceed as below (without using the touch command).
Write:
nano .Renviron
the .Renviron file will open. In it, add a line that says:
RETICULATE_PYTHON="enter your desired path here"
so, in my case, this is:
RETICULATE_PYTHON="/Library/Frameworks/Python.framework/Versions/3.7/bin/python3"
now save the file by exiting nano (ctrl+x) and clicking 'y' when it asks whether to save changes (press 'y' then press enter).
restart you RStudio. It should work now. I hope this is useful!
Background:
I'm using Windows. I know some of programming with python. I don't know much about batch, which I think I might need to do what I want.
I will show a example so it becomes more clear what I'm trying to do.
Example:
When using git, after you install it, you can call the git command from anywhere of your computer, you can execute git commands, like git init and this will create a git file in your current folder.
I don't know exactly how git works or what language they use but I want to do the same thing, create my own command that I can execute from anywhere in my computer after I "install" my program.
What I'm trying to do:
I want to make my own command and when I call it, it executes a python script.
e.g.
I install my program and it creates a command called myprogram and when I type myprogram in the command line, it's like if I typed python myprogram.py. And myprogram -someargument would be the same as python myprogram.py -someargument.
What I tried until now:
I'm searched for How to make a environment variable that runs Python script? but I never get exactly what I want, is always something like How do I set environment variable using Python script?.
Maybe I'm making the wrong question and the result I want are not showing?
I'm looking for a explanation on how to do this or at least a tutorial/guide.
Edit 1:
As UnholySheep said in the comments, it's not environment variable, its commands, so I changed the question even does what I want to know is the same thing.
Files you need:
First you need a python script (obviously) so I created a file called myprogram.py that have this simple line:
print("This should be from a command")
After you need to make a batch file, in my case I used a .cmd file called myprogram.cmd that have:
#ECHO OFF
python_directory\python.exe python_script_directory\myprogram.py %*
Configurations to make:
You need to set in PATH environment variable the location of the batch file batch_file_directory\myprogram.cmd
And now if you execute in the command line myprogram it will print This should be from a command.
You can also use .exe or .bat files.
I am not sure what I am supposed to be searching, because everything I have been trying to look up has not really given me the answers that I need.
If anyone can point me in the right direction of exactly what I should be looking at, I would greatly appreciate it. Basically, I want to know the best way to go about making a python program which I can distribute (not publicly).
Once someone has the file they run a script, or run the make command, and the result of this would be that the user can invoke the program from within any directory on the computer by just typing the name (and passing args) in the terminal.
I only know of one way to do this, which I believe is the wrong way. My idea was something as follows:
1.) A main folder, let's call it Ghoul. It would contain 3 files:
setup.sh
ghoul.sh
ghoul.py
2.) The user would have to run setup.sh, which would make ghoul.sh an executable and it would change the name to ghoul and then I would move it to /bin
3.) Within the ghoul file which is now in /bin, the file itself would contain "python /home/user/Ghoul/ghoul.py $#" And this would allow the program to run from any directory just by typing "ghoul"
I hope it's clear what I am trying to accomplish, I know this can't be the appropriate way of doing this. What should I be looking up and reading on to accomplish this? I would like to know how I can do this on Ubuntu and if also ..Windows.
I am also interested if I can limit the "ghoul" command to work only in the Ghoul directory, but of course in any directory that is within the Ghoul directory instead of from within any directory on the system.
Thank you.
On Unix like systems
#! /usr/bin/env python
in the very first line of your chmod +x script file will make it executable from the current directory using ./filename
If you want completely straightforward execution from anywhere you can put it on the path somewhere however you choose.
On windows its more complicated, if you want commandline execution the default install should give you the ability to execute
myscript.py
If its in your path. to drop the .py you need to get .py into the PATHEXT variable. Alternatively if it neds to be distributed to someone without any python install check out www.py2exe.org
I apologize if this is a duplicate, I couldn't find any other examples of this question.
I'm trying to write a program for natural language recognition, and I was reading a blog post where someone had attempted to do something similar and it recommended using these two lines to capture the output.
#capture output of script
./get-language.py | tee preptxt
I can't figure out what this code is attempting to do. I assume it's running the get-language file, but that syntax doesn't look correct to me. Could someone point me in the right direction?
On Unix systems you can run executable files with /path/to/my/executable.
This is nothing python specific.
As . is the current working directory, you are executing the get-language.py script located in the current directory.
However, there are two things you need to do, to get this working for your scripts:
1. add a shebang
This is the first line of your script, it tells the shell which program to use.
To use the python interpreter that is first in the PATH use:
#!/usr/bin/env python
2. Add the permissions to make your script executable:
You need to permit execution of your script. This can be done with chmod:
chmod +x myscript.py
The last part is a so called piping operation.
If you call two programs like this:
$ program_a | program_b
The output (stdout) of program_a is fed into program_b.
That's a shell thing, not Python. . is the current directory; you're running get-language.py from there.
This is not a line of python, but rather a shell script.
It is running a script called get-language.py (which I assume was described elsewhere on that blog and does the actual language processing), and then it is "piping" that output through the unix command line program tee, which stores the output in a file.
Piping takes the output of one program, and uses it as the input of another program.
I have created a little pre-commit hook in python. This hook works like a charm under Linux, but in Windows it keeps telling me:
error: cannot spawn .git/hooks/pre-commit: No such file or directory
I know there have been similar questions here about the same issue and the conclusion seams to be the shebang. My script has this on the very first line:
#!F:\PortableApps\PortablePython3.2\App\python.exe
It's also interesting to note that executing the script simply by writing .git/hooks/pre-commit works wonderful, but as soon as I try to commit, git spits out the above message.
Another interesting thing is, when I convert the encoding from ANSI to UTF-8 (using Notepad++), I get the following error when trying to execute the script:
.git/hooks/pre-commit: Cannot execute binary file
I'm using the following tools:
PortablePython 3.2.1.1
msysgit 1.7.6 (Portable)
I used the proxy-approach to make the python script work under windows (with msysgit). The complete script (with description on how I did it) might be found here: https://gist.github.com/1839424
Here is the important part about making it work under Windows
If you're working with Windows (and "msysgit"), it's a little more complicated. Since "msysgit" seems to have a problem handling the SHEBANG, you'll have to use a little trick to make the script executable (further information on this problem can be found here).
In order to make the script work, you'll want to remove the SHEBANG from the Python script ("pre-commit.py") and use a wrapper bash-script to call the interpreter. This script should look something like this:
#!/bin/sh
python .git/hooks/pre-commit.py
Store this script as a file called "pre-commit" (no file-ending). This assumes that you have Python in your PATH. If you don't, you can also specify the full path to your interpreter-executable.
This script will be called by "git commit" and call the python-script to check for the huge files. The path after the SHEBANG should not be changed, as "msysgit" will remap it automatically. You must specify a path relative to the repo-root for the Python script to be executed (because thats from where the script is called).
Afterwards you'll want to copy both the wrapper-file ("pre-commit") and the Python-script ("pre-commit.py") to your repos ".git/hooks"-directory, personalize the Python-script ("max_file_size" and "git_binary_path") and mark the "pre-commit"-file executable.