I am working with my Raspberry Pi 2 B+ and I am using Raspbian. I have a python script located at /home/pi/Desktop/control/gpio.py
When I type /home/pi/Desktop/control/gpio.py into the command line, I get the message
bash: /home/pi/Desktop/control/gpio.py Permission denied
I have tried running sudo -s before running that command also but that doesnt work. My python script is using the Rpi.GPIO library.
If someone could please explain why I am getting this error it would be appreciated!
You will get this error because you do not have the execute permission on your file. There are two ways to solve it:
Not executing the file in the first place. By running python gpio.py python will load the file by reading it, so you don't need to have execute permission.
Granting yourself execute permission. You do this by running chmod u+x yourfile.py.
However, doing so will not work unless you add a shebang at the top of your python program. It will let your linux know which interpreter it should start. For instance:
#!/usr/bin/env python
This would try to run python using your current $PATH settings. If you know which python you want, put it here instead.
#!/usr/bin/python3
Remember the shebang must be the very first line of your program.
do like this maybe work:
cd /home/pi/Desktop/control/
python gpio.py
Because gpio.py is not a executable file, you should run it by python instead
Related
I am running a (bio)python script which results in the following error:
from: can't read /var/mail/Bio
seeing as my script doesn't have anything to with mail, I don't understand why my script is looking in /var/mail.
What seems to be the problem here? i doubt it will help as the script doesn't seem to be the problem, but here's my script anyway:
from Bio import SeqIO
from Bio.SeqUtils import ProtParam
handle = open("examplefasta.fasta")
for record in SeqIO.parse(handle, "fasta"):
seq = str(record.seq)
X = ProtParam.ProteinAnalysis(seq)
print X.count_amino_acids()
print X.get_amino_acids_percent()
print X.molecular_weight()
print X.aromaticity()
print X.instability_index()
print X.flexibility()
print X.isoelectric_point()
print X.secondary_structure_fraction()
what is the problem here? bad python setup? I really don't think it's the script.
No, it's not the script, it's the fact that your script is not executed by Python at all. If your script is stored in a file named script.py, you have to execute it as python script.py, otherwise the default shell will execute it and it will bail out at the from keyword. (Incidentally, from is the name of a command line utility which prints names of those who have sent mail to the given username, so that's why it tries to access the mailboxes).
Another possibility is to add the following line to the top of the script:
#!/usr/bin/env python
This will instruct your shell to execute the script via python instead of trying to interpret it on its own.
I ran into a similar error when trying to run a command.
After reading the answer by Tamás,
I realized I was not trying this command in Python but in the shell (this can happen to those new to Linux).
Solution was to first enter in the Python shell with the command python
and when you get these >>>
then run any Python commands.
Same here. I had this error when running an import command from terminal without activating python3 shell through manage.py in a django project (yes, I am a newbie yet). As one must expect, activating shell allowed the command to be interpreted correctly.
./manage.py shell
and only then
>>> from django.contrib.sites.models import Site
Put this at the top of your .py file (for Python 2.x)
#!/usr/bin/env python
or for Python 3.x
#!/usr/bin/env python3
This should look up the Python environment. Without it, it will execute the code as if it were not Python code, but shell code. If you need to specify a manual location of the Python environment, put
#!/#path/#to/#python
for Mac OS just go to applications and just run these Scripts Install Certificates.command and Update Shell Profile.command, now it will work.
For Flask users, before writing the commands, first make sure you enter the Flask shell using:
flask shell
I wrote some code on my laptop and now I am trying to run this code. But it give me the output : Permission denied
Usually that should only happen if a different user would try to access it. But I am the user who wrote it and is trying to run it now. I feel like this will be an easy issue to resolve but any help would be nice! Thanks.
I wrote and saved the code in IDLE python. Once I finished I tried running it in my Terminal (I have the macOS Mojave Version 10.14.5) but then I ran into the issue.
Evandros-MBP:~ evandro$ ./Desktop/FunCodes/pwd.py
This is how I tried to call up the code. I don't see any issues here.
Instead of calling the script with
./Desktop/FunCodes/pwd.py
try using
python ./Desktop/FunCodes/pwd.py
or also
python3 ./Desktop/FunCodes/pwd.py
if you want to execute it with python3 instead of python2.
Explanation
When you write ./some-file in the terminal (without writing python before the file path), the terminal executes it as a bash file (no matter if the file has a .sh extension or not). Of course, since your file is a python file, this will fail. But even before it fails, since your python file has no permission to be executed, permission will be denied and bash won't even start.
On creation, the file only has read and write permissions. Add a shebang pointing to the Python interpreter on the script's first line, for example #!/usr/bin/env python. Also, your script is not marked as executable, in order to do that you need to use:
chmod +x pwd.py
Otherwise you will only be able to run it with Python, with
python pwd.py
I am new to both Python and Linux and as such request simple explanations with minimal assumed knowledge where possible please, however I am more than willing to invest time and effort to learn.
I have a Raspberry Pi 2 (Model B V1.1) that is running Linux. I interact with this pi via putty.
I am trying to create a simple competitive reflex game, consisting of 2 buttons and a single LED. My goal is to have the LED light up after a short interval, and the first player to press their button wins.
I am writing the script for this with python (specifically 2.7.3)
My issue is that i am unable to run ANY .py file from within putty, i always receive the same error:
Syntax error: word unexpected (expecting ")")
To determine if the issue was an error in my code, i created a very very simple .py file, to check if the same error occurs, and it did. So i currently believe even if my code was functional, something is stopping me from running ANY .py file.
The process I am using is as follows:
First I create a new python file from within putty:
sudo nano test.py
Next I enter my python code (very simple for now, as i cannot get ANY .py file to run)
for each in range(5):
print 'hello'
I then press CTRL + O to write the file, hit enter, then CTRL + X to exit
Finally, I make the file executable using
sudo chmod u+x test.py
and try to run it
sudo ./test.py
again, a similar error occurs
Syntax error: "(" unexpected
I then decided to enter the code directly into the python shell, using
sudo python
>>>for each in range(5):
... print 'hello'
This time the output is the desired outcome:
hello
hello
hello
hello
hello
So there is no problem in executing python code directly from the shell, I am just unable to execute any previously saved .py file
Any insight into what could be causing this is much appreciated, and I apologise if I have not provided enough information to be useful for you.
Thanks in advance!
Short answer: Either run these as python filename.py, or else add the line #!/usr/bin/python to the top of your Python scripts.
Long answer: When you run a file from the command line in Linux (which is what the Raspberry Pi is running), by default it assumes that the file is a shell script file (usually Bash script). So it uses the Bash shell (or some other shell, but it's usually Bash) to interpret the file, and Bash doesn't know Python syntax. If you want to run your file using a different interpreter (Python, in this case), you have to add a "magic line" at the top of the file starting with #! (usually pronounced "hash-bang", and sometimes pronounced "shebang" for short). Following the #! characters is the full path of the interpreter to use, e.g. /usr/bin/python for Python scripts. (You can also use /usr/bin/env python as another answer suggested; I prefer /usr/bin/python because it's impossible to get the wrong Python interpreter that way. But that's getting into advanced topics that may be more than you need right now.)
So when you put the line #!/usr/bin/python at the top of your Python scripts, you're telling the Linux system which interpreter to run the program with, and then it should All Just Work™.
Also, STOP using sudo to edit and run these! That's just asking for trouble.
If you wish to execute like this you need the following line as the first line
#!/usr/bin/env python
This will tell bash (or equivalent) to execute the file with the Python interpreter.
If you don't want to do that then you can execute the script like this:
$ python test.py
If you go this route then you don't need to grant execute permissions on the script itself.
Also, scripts shouldn't be executed with sudo unless absolutely necessary.
Let's say I want to use a shell script to run a python file, called test.py, which is in a directory called Test in my home directory. I tried the following code, which does not work:
#!/bin/bash
echo "Starting."
module load gcc/4.8.2
module load python/3.4.1
echo "Modules loaded."
$HOME/Test/test.py
exit 0
I do not believe that how I am trying to run the program ($HOME/Test/test.py) works. I have not been able to determine how to do this, despite searching for a long time. Any help would be appreciated.
This is likely one of the following, or it may be a combination of both.
The python script is not executable. Fix with:
chmod u+x $HOME/Test/test.py
The script does not start with a #! line pointing to python. Fix that by making this the first line of test.py:
#!/usr/bin/env python
You can also use a full path instead of using /usr/bin/env to use $PATH to resolve the name.
#!/usr/local/bin/python
I want to run my python function in console like this:
my_function_name
at any directory, I tried to follow arajek's answer in this question:
run a python script in terminal without the python command
but I still need to call my_function_name.py to make it work. If I call only my_function_name, the console will inform me command not found . I also tried to add a symbolic link with this answer: Running a Python Script Like a Built-in Shell Command but it failed
sudo ln -s my_function_name.py /home/thovo/test/my_function_name
ln: failed to create symbolic link ‘/home/thovo/test/my_function_name/my_function_name.py’: File exists
Change the name of the script to no longer have the .py extension.
Add this shebang to the top of your file: #!/usr/bin/env python and remove the file extension.