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How to use Popen to open a file with space in its name with default program in windows? [duplicate]

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Using subprocess.Popen (shell=True) with windows folders
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Closed 2 years ago.
The following code can open the test.txt file with notepad
subprocess.Popen(['start','test.txt'],shell=True)
But this won't open a file with a space in its name like 'the test.txt'.
I've tried using raw string(r'...'), double quote on cmd, '%20' to substitute the space, but none of that works.

Passing a list of arguments with shell=True happens to generally work on Windows, but is really never correct. Of course, start is a shell (cmd) command, so you need a shell here; but then, you also need to quote the string for the shell.
subproces.run('start "the test.txt"', shell=True)
Notice also that I switched to subprocess.run(); you generally want to avoid raw Popen whenever you can, as also suggested in the documentation.

It's much easier to rename the file with an underscore or dash etc.
I had a similar issue once with a client. I'm fairly certain we concluded by renaming by hand all of the necessary files to replace a space with an underscore.
Unless python have released a patch (or indeed, I was oblivious), I think it may be impossible.
Python reads a space and goes "okay, thats that command, what's next?" and then reads whatever follows the space, excluding certain things like string variables.
Take these lines
import os
os.system("start EXCEL.EXE my workbook.xlsb")
Python of course imports the os module here, then in line two it runs the os.system command with the parameters; start, EXCEL.EXE, my, workbook.xlsb
in fact it doesn't, once it reaches the filename "my" without an extension it quits and throws an error in the shell.

Can't get working command line on prompt to work on subprocess

I need to extract text from a PDF. I tried the PyPDF2, but the textExtract method returned an encrypted text, even though the pdf is not encrypted acoording to the isEncrypted method.
So I moved on to trying accessing a program that does the job from the command prompt, so I could call it from python with the subprocess module. I found this program called textExtract, which did the job I wanted with the following command line on cmd:
"textextract.exe" "download.pdf" /to "download.txt"
However, when I tried running it with subprocess I couldn't get a 0 return code.
Here is the code I tried:
textextract = shlex.split(r'"textextract.exe" "download.pdf" /to "download.txt"')
subprocess.run(textextract)
I already tried it with shell=True, but it didn't work.
Can anyone help me?

I was able to get the following script to work from the command line after installing the PDF2Text Pilot application you're trying to use:
import shlex
import subprocess
args = shlex.split(r'"textextract.exe" "download.pdf" /to "download.txt"')
print('args:', args)
subprocess.run(args)
Sample screen output of running it from a command line session:
> C:\Python3\python run-textextract.py
args: ['textextract.exe', 'download.pdf', '/to', 'download.txt']
Progress:
Text from "download.pdf" has been successfully extracted...
Text extraction has been completed!
The above output was generated using Python 3.7.0.
I don't know if your use of spyder on anaconda affects things or not since I'm not familiar with it/them. If you continue to have problems with this, then, if it's possible, I suggest you see if you can get things working directly—i.e. running the the Python interpreter on the script manually from the command line similar to what's shown above. If that works, but using spyder doesn't, then you'll at least know the cause of the problem.

There's no need to build a string of quoted strings and then parse that back out to a list of strings. Just create a list and pass that:
command=["textextract.exe", "download.pdf", "/to", "download.txt"]
subprocess.run(command)
All that shlex.split is doing is creating a list by removing all of the quotes you had to add when creating the string in the first place. That's an extra step that provides no value over just creating the list yourself.

Python subprocess.call with multiline string EOF

I've hit a issue that I don't really understand how to overcome. I'm trying to create a subprocess in python to run another python script. Not too difficult. The issue is I'm unable to get around is EOF error when a python file includes a super long string.
Here's an example of what my files look like.
Subprocess.py:
### call longstr.py from the primary pyfile
subprocess.call(['python longstr.py'], shell = True)
Longstr.py
### called from subprocess.py
### the actual string is a lot longer; this is an example to illustrate how the string is formatted
lngstr = """here is a really long
string (which has many n3w line$ and "characters")
that are causing the python file to state the file is ending early
"""
print lngstr
Printer error in terminal
SyntaxError: EOF while scanning triple-quoted string literal
As a work around, I tried to remove all linebreaks as well as all spaces to see if it was due to it being multi-line. That still returned the same result.
My assumption is that when the subprocess is running and the shell is doing something with the file contents, when the new line is reached the shell itself is freaking out and that's what's terminating the process; not the file.
What is the correct workaround for having subprocess run a file like this?
Thank you for your help.

Answering my own question here; my problem was that I didn't file.close() before trying to execute a subprocess.call.
If you encounter this problem, and are working with recently written files this could be your issue too. Thank you to everyone who read or responded to this thread.

Specifying filename in os.system call from python

I am creating a simple file in python to reorganize some text data I grabbed from a website. I put the data in a .txt file and then want to use the "tail" command to get rid of the first 5 lines. I'm able to make this work for a simple filename shown below, but when I try to change the filename (to what I'd actually like it to be) I get an error. My code:
start = 2010
end = 2010
for i in range(start,end+1)
year = str(i)
...write data to a file called file...
teamname=open(file).readline() # want to use this in the new filename
teamfname=teamname.replace(" ","") #getting rid of spaces
file2 = "gotdata2_"+year+".txt"
os.system("tail -n +5 gotdata_"+year+".txt > "+file2)
The above code works as intended, creating file, then creating file2 that excludes the first 5 lines of file. However, when I change the name of file2 to be:
file2 = teamfname+"_"+year+".txt"
I get the error:
sh: line 1: _2010.txt: command not found
It's as if the end of my file2 statement is getting chopped off and the .txt part isn't being recognized. In this case, my code outputs a file but is missing the _2010.txt at the end. I've double checked that both year and teamfname are strings. I've also tried it with and without spaces in the teamfname string. I get the same error when I try to include a os.system mv statement that would rename the file to what I want it to be, so there must be something wrong with my understanding of how to specify the string here.
Does anyone have any ideas about what causes this? I haven't been able to find a solution, but I've found this problem difficult to search for.

Without knowing what your actual strings are, it's impossible to be sure what the problem is. However, it's almost certainly something to do with failing to properly quote and/or escape arguments for the command line.
My first guess would be that you have a newline in the middle of your filename, and the shell is truncating the command at the newline. But I wouldn't bet too heavily on that. If you actually printed out the repr of the pathname, I could tell you for sure. But why go through all this headache?
The solution to almost any problem with os.system is to not use os.system.
If you look at the docs, they even tell you this:
The subprocess module provides more powerful facilities for spawning new processes and retrieving their results; using that module is preferable to using this function. See the Replacing Older Functions with the subprocess Module section in the subprocess documentation for some helpful recipes.
If you use subprocess instead of os.system, you can avoid the shell entirely. You can also pass arguments as a list instead of trying to figure out how to quote them and escape them properly. Which would completely avoid the exact problem you're having.
For example, if you do this:
file2 = "gotdata2_"+year+".txt"
with open(file2, 'wb') as f:
subprocess.check_call(['tail', '-n', '+5', "gotdata_"+year+".txt"], stdout=f)
Then, if you change that first line to this:
file2 = teamfname+"_"+year+".txt"
It will still work even if teamfname has a space or a quote or another special character in it.
That being said, I'm not sure why you want to use tail in the first place. You can skip the first 5 lines just as easily directly in Python.

What to do with "The input line is too long" error message?

I am trying to use os.system() to call another program that takes an input and an output file. The command I use is ~250 characters due to the long folder names.
When I try to call the command, I'm getting an error: The input line is too long.
I'm guessing there's a 255 character limit (its built using a C system call, but I couldn't find the limitations on that either).
I tried changing the directory with os.chdir() to reduce the folder trail lengths, but when I try using os.system() with "..\folder\filename" it apparently can't handle relative path names. Is there any way to get around this limit or get it to recognize relative paths?

Even it's a good idea to use subprocess.Popen(), this does not solve the issue.
Your problem is not the 255 characters limit, this was true on DOS times, later increased to 2048 for Windows NT/2000, and increased again to 8192 for Windows XP+.
The real solution is to workaround a very old bug in Windows APIs: _popen() and _wpopen().
If you ever use quotes during the command line you have to add the entire command in quoates or you will get the The input line is too long error message.
All Microsoft operating systems starting with Windows XP had a 8192 characters limit which is now enough for any decent command line usage but they forgot to solve this bug.
To overcome their bug just include your entire command in double quotes, and if you want to know more real the MSDN comment on _popen().
Be careful because these works:
prog
"prog"
""prog" param"
""prog" "param""
But these will not work:
""prog param""
If you need a function that does add the quotes when they are needed you can take the one from http://github.com/ssbarnea/tendo/blob/master/tendo/tee.py

You should use the subprocess module instead. See this little doc for how to rewrite os.system calls to use subprocess.

You should use subprocess instead of os.system.
subprocess has the advantage of being able to change the directory for you:
import subprocess
my_cwd = r"..\folder\"
my_process = subprocess.Popen(["command name", "option 1", "option 2"], cwd=my_cwd)
my_process.wait() # wait for process to end
if my_process.returncode != 0:
print "Something went wrong!"
The subprocess module contains some helper functions as well if the above looks a bit verbose.

Assuming you're using windows, from the backslashes, you could write a .bat file from python and then os.system() on that. It's a hack.

Make sure when you're using '\' in your strings that they're being properly escaped.
Python uses the '\' as the escape character, so the string "..\folder\filename" evaluates to "..folderfilename" since an escaped f is still an f.
You probably want to use
r"..\folder\filename"
or
"..\\folder\\filename"

I got the same message but it was strange because the command was not that long (130 characters) and it used to work, it just stopped working one day.
I just closed the command window and opened a new one and it worked.
I have had the command window opened for a long time (maybe months, it's a remote virtual machine).
I guess is some windows bug with a buffer or something.