Python oserror errno 8 exec format error

The oserror: [errno 8] exec format error often can be encountered in different instances on LINUX systems. This article explains its origination and the reasons behind it. Furthermore, it also decodes interesting tricks that can be easily done to solve those reasons. This short guide is the best resource to aid your scripting skills in the right direction.

Why Is Oserror: [Errno 8] Exec Format Error Happening?

Oserror: [errno 8] exec format error originates due to a combination of errors while executing a script in a UNIX server. Some common reasons are the absence of a shebang line, an invalid format of the script, an incorrect path to ffmpeg, and not supported Werkzeug version.

– Absence of a Shebang Line

The location of a shebang line is at the top of a shell script. Its absence can cause the oserror: (errno exec format error subprocess call as attempts are made to directly execute the script. The following is a code example that results in the error by reproducing this issue:

>>> with open (‘a’,’w’) as f: f.write (‘exit 0’) # creation of the script
…
>>> import os
>>> os.chmod (‘a’, 0b111101101) # rwxr-xr-x make it executable
>>> os.execl (‘./a’, ‘./a’) # execute it

The placement of a shebang line is linked with the occurrence of the oserror: (errno exec format error python script. Even though its inclusion followed by the executable of the relevant shell holds no mandatory purpose for the implementation of a script. It means that writing a simple script with the involvement of the execute permission and running it using the “.” operator is possible.

The implementation can be executed by the relevant login shell. The following is a code example that runs successfully:

cat sample
echo “Hello World”
chmod u+x sample
./sample

The output of this implementation is:

Importance of a Shebang Line for the Error

Considering its optional inclusion above, a shebang line is still important in determining the occurrence of the oserror: (errno exec format error mac. The “#!/bin/bash line is included in the shell scripts right at the start of any script. Nowadays, there are different shells available for both UNIX and LINUX systems.

Even though the general syntax may be common among them, different shells have different ways of handling the specific aspects of a script.

This is why the absence of a shebang line causes the oserror errno 8 exec format error robot framework. The lack of specification for a correct shell interpreter corresponds to the failed implementation of a script. In this way, there can be a variation of results with scripts that run in different shells.

– Invalid Format of Script

The display of the oserror: (errno exec format error flask can also be an indication of the possible invalid format of the relevant script. The following snippet can be run to find out the aspects of the format. After this, they can be used to conduct a comparison between the architecture and the output of $ uname –m:

$ file /usr/local/bin/script

– Incorrect Path to Ffmpeg

The oserror: (errno exec format error ffmpeg can occur if the path taken to either ffprobe or ffmpeg is inaccurate. In another case, the files that are being pointed out are not the relevant valid binaries. As a result, the precompiled ffmpeg binaries may not run on the OSX box, although they may run on Synology.

In addition, a ffmpeg executable may already be installed within the Video Station package of Synology Diskstation. The following is a snippet that shows what it may look like:

DiskStation> find / -type d -name ffmpeg
/volume1/@appstore/MediaServer/lib/ffmpeg
/volume1/@appstore/VideoStation/lib/ffmpeg
/volume1/@appstore/AudioStation/lib/ffmpeg

– Werkzeug Version Not Supported

Since version 0.14 of Werkzeug is not supported, this may lead to the occurrence of the oserror: (errno exec format error docker. The involvement of the docker is a new behavior in its version 0.15, where going down to Werkzeug 0.14.1 might work. Therefore, the issue with the relevant file must be corrected.

How Can the Error Be Solved?

Oserror [errno 8] can be fixed by adding a shebang line that acts as a great counter to the error. Parsing the command line is another measure that can be taken to fix the error. Moving on, disabling the debug mode and functioning executables and execution permissions are also some options that can counter the error.

– Adding a Shebang Line

A shebang line can be added with #!/bin/sh prepended at the top of the relevant script if it is a shell script. Here is an example that shows how it can be done with the execution of exit 0 and no occurrence of errors:

>>> with open(‘a’,’w’) as f: f.write(‘#!/bin/shnexit 0’)
>>> os.execl(‘./a’, ‘./a’)

Syntax of a Shebang: A Quick Glance

As a combination of the exclamation mark and pound key, a shebang acts as a character combination that possesses a specific meaning in scripting. It is used as the first member of the first line in every script. Its usage corresponds to the specification of the interpreter that enables the relevant script to run by default.

For example, “#!/bin/bash” can be the first line of any script and signify that the interpreter of the implementation is a bash shell. The first line can also be “#!/bin/zsh” which corresponds to the Z shell as the interpreter. The syntax of a shebang (#!) enables the users to differentiate between itself and comments in shell scripts as both of them have different meanings.

– Parsing the Command Line

The invalid format of the script can be fixed by parsing the command line. Parsing is conducted by the shell on POSIX systems in which the aspects of a valid format are iterated. For example, there are no spaces around the equals “=” sign. This can be seen in the following script:

#!/usr/bin/env python
import sys
print(sys.argv)

This is the implementation when this script runs in the shell:

$ /usr/local/bin/script hostname = ‘<hostname>’ -p LONGLIST

The following is the output of this implementation in which there are no spaces around ‘=’. Moreover, there is an addition of quotes around <hostname> so that the redirection meta characters ‘<>’ can be escaped:

[‘/usr/local/bin/script’, ‘hostname’, ‘=’, ‘<hostname>’, ‘-p’, ‘LONGLIST’]

– Functioning Executables and Execution Permissions

The error caused by an incorrect path to ffmpeg can be solved by ensuring that the executables are functioning correctly. Furthermore, they must have execution permissions with certain precompiled ffmpeg binaries taken up as well. These binaries can be swapped in to keep a check on the persistence of the error. As for the snippet above, the autoProcess.ini path can be updated so that it corresponds to the new location:

ffmpeg = /volume1/@appstore/VideoStation/lib/ffmpeg

Disabling the Debug Mode

The file issue can be corrected by disabling the debug mode so that the reloader cannot be used. Keep in mind that neither debug=True nor set FLASK _DEBUG=0 should be debugged. With this, the issue can never occur with the downside of not being able to use the reloader.

In addition, it can be fixed if there is an interpreter line for those files that are marked as executable like #!/usr/bin/env python3. The following is a snippet that shows how to do that:

if __name__ == “__main__”:
connexion_app.run(host=”0.0.0.0″, port=constants.API_PORT, debug=True)

Conclusion

This article put forward a layout of the occurrence of the error in many instances. Let’s look at the main points:

• The error can occur if the shebang line is absent at the top of the script.
• An incorrect path taken to either ffmpeg or ffprobe can also result in the occurrence of the error.
• Although the docker is involved in version 0.15 of Werkzeug, its version 0.14 is not supported; therefore, the error can originate.
• A shebang line is a combination of the exclamation mark and pound key and can be added to the top of the script.
• The executables should function properly and contain their execution permissions accompanied by precompiled ffmpeg binaries.

This article can help you whenever you are on the lookout for any information about this error.

OSError: [Errno 8] Exec Format Error in Python

The subprocess module in Python allows you to run commands by creating new processes. When running a shell script using its methods, sometimes you may get an OSError: [Errno 8] Exec format error in Linux.

The problem Exec format error is raised when the script is directly run and not through the correct interpreter. It occurs if there is no shebang line at the beginning of the script file.

This tutorial will teach you to fix Linux’s OSError: [Errno 8] Exec format error .

Recreate OSError: [Errno 8] Exec format error in Linux

First, let’s recreate OSError: [Errno 8] Exec format error in Linux.

The following is a Bash script myshell.sh that returns Welcome to DelftStack Tutorials .

Below is a Python script, myscript.py , that runs the above script using subprocess.Popen() .

Run the Python script in the terminal.

As you can see, it returns the error OSError: [Errno 8] Exec format error .

Add #!/bin/sh to Fix OSError: [Errno 8] Exec format error in Linux

The best way to solve this issue is by adding #!/bin/sh at the top of the shell script file myshell.sh . It ensures that the system uses the right interpreter to run the .sh script.

Edit the myshell.sh file with any editor and add the below lines.

Now run the Python script to see the result.

Use sh to Fix OSError: [Errno 8] Exec format error in Linux

You can also specify sh in Python script in the command that runs the shell script file.

Here is an example of it.

Next, run the Python script file.

Now you know how to solve OSError: [Errno 8] Exec format error and run shell scripts using Python in Linux. We hope you find this tutorial helpful.

Rohan is a learner, problem solver, and web developer. He loves to write and share his understanding.

Источник

OSError: [Errno 8] Exec format error #93

I just did a fresh install of Ubuntu LTS 14.04 on a virtual machine, and installed using sudo pip install dronekit-sitl .

When trying to open a instance, I get this error:

Appears that dronekit-sitl is identifying my system as ‘win32’.

The text was updated successfully, but these errors were encountered:

One potential issue is that I think the version of PyPi is out of date. Try install sitl from github:

Ok, I uninstalled dronekit-sitl , then I did: sudo pip install git+https://github.com/dronekit/dronekit-sitl

Then again tried to open it:

Its a bugger. I’ve not been able to reproduce this on this same ubuntu in a VM 🙁

@peterbarker Any suggestions? We’ve seen this before, but I personally can’t get it to «fail».

I had an old VM with Ubuntu 14.04. updated and the installed and worked excellent.

Then I created a new one, brand new, «fresh» VM with the same ubuntu 14.04 and this problem started.

I just completely reinstalled VM on Windows 10 of Ubuntu 14.04 and it worked fine . As you say, same Ubuntu 14.04. I don’t doubt that you have a problem, I just can’t get it to fail in the same way.

I manage to get a work-around for this situation. I compiled ArduPilot like this:

And then to execute: dronekit-sitl ./ardupilot/ArduCopter/ArduCopter.elf

Is not ideal. or as easy as just using pip, but is working.

Interesting. The fact that you can launch native binaries implies that the original error report is accurate — i.e. that you’ve been downloading binaries that aren’t native or aren’t detected as native. @peterbarker Any ideas how we might debug this?

OK, can you make that release? . or do you not have the magic power?

Hi, I’m having the same issue on Ubuntu 14.04.4 LTS using master. Any news on this?

Traceback (most recent call last):
File «../../base/android/jni_generator/jni_generator.py», line 1109, in
sys.exit(main(sys.argv))
File «../../base/android/jni_generator/jni_generator.py», line 1105, in main
GenerateJNIHeader(input_file, output_file, options)
File «../../base/android/jni_generator/jni_generator.py», line 1022, in GenerateJNIHeader
input_file, options)
File «../../base/android/jni_generator/jni_generator.py», line 576, in CreateFromFile
return JNIFromJavaSource(contents, fully_qualified_class, options)
File «../../base/android/jni_generator/jni_generator.py», line 531, in init
contents = self._RemoveComments(contents)
File «../../base/android/jni_generator/jni_generator.py», line 564, in _RemoveComments
stderr=subprocess.PIPE)
File «/usr/lib/python2.7/subprocess.py», line 710, in init
errread, errwrite)
File «/usr/lib/python2.7/subprocess.py», line 1327, in _execute_child
raise child_exception
OSError: [Errno 8] Exec format error

Almost certainly running SITL on an ARM platform. Binaries are no supplied, though you can build your own.

What could I do?
It never happened to me.

I think this error is from that dronekit sitl can not support 32 bit linux OS.
Below is my try, please refer.
on Ubuntu 14.04 64bit with intel PC -> works fine
on Ubuntu mate 16.04 with Raspberry -> works fine
on Ubuntu 14.04 with Odroid ux4 -> Error same as above

Same issue here. Tried it on Odroid XU4 running Mate 16.04 resulted in the same error. Any fix for that?

Hi,
Can any help me to solve the below issue :
Traceback (most recent call last):
File «../../base/android/jni_generator/jni_generator.py», line 1109, in
sys.exit(main(sys.argv))
File «../../base/android/jni_generator/jni_generator.py», line 1105, in main
GenerateJNIHeader(input_file, output_file, options)
File «../../base/android/jni_generator/jni_generator.py», line 1018, in GenerateJNIHeader
jni_from_javap = JNIFromJavaP.CreateFromClass(input_file, options)
File «../../base/android/jni_generator/jni_generator.py», line 521, in CreateFromClass
stderr=subprocess.PIPE)
File «/usr/local/lib/python2.7/subprocess.py», line 390, in init
errread, errwrite)
File «/usr/local/lib/python2.7/subprocess.py», line 1024, in _execute_child
raise child_exception
OSError: [Errno 2] No such file or directory
external/chromium_org/ui/gl/surface_jni_headers.target.linux-arm.mk:22: recipe for target ‘/home/vipul/files/out/target/product/bacon/obj/GYP/shared_intermediates/ui/gl/jni/Surface_jni.h’ failed
make: *** [/home/vipul/files/out/target/product/bacon/obj/GYP/shared_intermediates/ui/gl/jni/Surface_jni.h] Error 1
make: *** Waiting for unfinished jobs.
external/chromium_org/third_party/sqlite/amalgamation/sqlite3.c: In function ‘fts3SnippetFunc’:
external/chromium_org/third_party/sqlite/amalgamation/sqlite3.c:124201:11: warning: ‘iS’ may be used uninitialized in this function [-Wmaybe-uninitialized]
external/chromium_org/third_party/sqlite/amalgamation/sqlite3.c:124193:13: note: ‘iS’ was declared here
external/chromium_org/third_party/sqlite/amalgamation/sqlite3.c: In function ‘recoverOpen’:
external/chromium_org/third_party/sqlite/amalgamation/sqlite3.c:112080:24: warning: ‘pLeafCursor’ may be used uninitialized in this function [-Wmaybe-uninitialized]
external/chromium_org/third_party/sqlite/amalgamation/sqlite3.c: In function ‘unixOpen’:
external/chromium_org/third_party/sqlite/amalgamation/sqlite3.c:29202:21: warning: ‘openMode’ may be used uninitialized in this function [-Wmaybe-uninitialized]
external/chromium_org/third_party/sqlite/amalgamation/sqlite3.c:29195:12: note: ‘openMode’ was declared here

Thanks in advance 🙂

I am trying to interface the raspberry pi with the pixhawk through serial pins on raspberry pi. I am able to get a connection between the two.

I get the following messages after setting up the connection
i@raspberrypi:

$ sudo -s
root@raspberrypi:/home/pi# mavproxy.py —master=/dev/ttyACM0 —baudrate 57600 —aircraft plane
Connect /dev/ttyACM0 source_system=255
no script plane/mavinit.scr
Log Directory: plane/logs/2017-12-15/flight1
Telemetry log: plane/logs/2017-12-15/flight1/flight.tlog
MAV> Waiting for heartbeat from /dev/ttyACM0
*o]l`:H9%online system 1
ALT_HOLD> Mode ALT_HOLD
[S$ ;APM: APM:Copter V3.5.4 (284349c3)
APM: PX4: 0384802e NuttX: 1bcae90b
APM: Frame: QUAD
APM: PX4v3 00490021 33355119 38393235
Received 773 parameters
Saved 773 parameters to plane/logs/2017-12-15/flight1/mav.parm
fence breach
mode
ALT_HOLD> (‘Available modes: ‘, [‘RTL’, ‘POSHOLD’, ‘LAND’, ‘OF_LOITER’, ‘STABILIZE’, ‘AUTO’, ‘GUIDED’, ‘THROW’, ‘DRIFT’, ‘FLIP’, ‘AUTOTUNE’, ‘ALT_HOLD’, ‘BRAKE’, ‘LOITER’, ‘AVOID_ADSB’, ‘POSITION’, ‘CIRCLE’, ‘SPORT’, ‘ACRO’])

After this i tried writing a python code to get some data from pixhawk
I followed the steps here
http://python.dronekit.io/guide/quick_start.html#installation

but then i get this error
pi@raspberrypi:

$ sudo python hello.py
Start simulator (SITL)
Starting copter simulator (SITL)
Downloading SITL from http://dronekit-assets.s3.amazonaws.com/sitl/copter/sitl-linux-copter-3.3.tar.gz
Download Complete.
Payload Extracted.
Ready to boot.
Failed to run (/root/.dronekit/sitl/copter-3.3/apm)
Traceback (most recent call last):
File «hello.py», line 3, in
sitl = dronekit_sitl.start_default()
File «/usr/local/lib/python2.7/dist-packages/dronekit_sitl/init.py», line 454, in start_default
sitl.launch(sitl_args, await_ready=True, restart=True)
File «/usr/local/lib/python2.7/dist-packages/dronekit_sitl/init.py», line 253, in launch
caps = ArdupilotCapabilities(self.path)
File «/usr/local/lib/python2.7/dist-packages/dronekit_sitl/init.py», line 165, in init
self.has_defaults_path = «—defaults path» in helptext
UnboundLocalError: local variable ‘helptext’ referenced before assignment

Any help would be appreciated. Stuck at this from quiet long.

Источник

0.15.0 causes OSError: [Errno 8] Exec format error: in Docker for Windows #1482

The new 0.15.0 does not run in Docker for Windows. Have not tried Docker on other platforms.

Minimal example with Flask.

Run docker build -t flask_test . and then docker run flask_test .
Error in container:

Uncomment the first line in requirements.txt and it runs properly after rebuild.

The text was updated successfully, but these errors were encountered:

Hi same issue here. Tested on

• Centos 7.4 with python 3.6
• Mac OSX 10.14.3 with python 3.7

This is caused by the changes in _get_args_for_reloading() in _reloading.py.

Given the code above in a file called app.py, with cwd() being /home/user/Projects/test/

_get_args_for_reloading() yields the following:

Prepending /home/user/.virtualenvs/test-ChRUEUMK/bin/python to the path does fix the issue.

@shinuza check if app.py is executable, if yes — set chmod 644 app.py. Or second way, add shebang on the top of app.py like #!/usr/bin/env python

@shinuza there https://github.com/pallets/werkzeug/blob/0.15.x/src/werkzeug/_reloader.py#L90 lines 90-94 the «‘/home/user/.virtualenvs/test-ChRUEUMK/bin/python’» was removed if app.py executable.
and OSError: [Errno 8] Exec format error: ‘/usr/src/app/app.py happened because app.py doesn’t have shebang line (https://stackoverflow.com/questions/27606653/oserror-errno-8-exec-format-error)

@kamyanskiy I just figured this out reading the code but the error should be as cryptic as it is right now.

Also, if I explicitly run python app.py , then the subprocess should not make any assumption and change the way I run the application. i.e: working with a virtual machine with shared folder makes every files executable by default.

@shinuza I don’t think its a critical bug, in other words its a bit stricter now than before. So I shouldn’t have executable app.py without shebang, it doesn’t make sense. And second I shouldn’t run executable with shebang like «python app.py». But I agree, probably that was unexpected for you as for me 🙂 To workaround just add shebang to your app.py, I hope this will help.

If you mark a script as executable, you should add a corresponding interpreter comment to the top. You can use a tool like pre-commit’s check-executables-have-shebangs hook to enforce that.

If you don’t intend for a script to be directly executable, and want to require python script.py instead, then you should not mark it executable.

As I said, I agree with the main logic here. I disagree with the way the error is dealt with as well as the fact that the error message is unintelligible unless you know the know the technical details or read the code. It should at least be documented in the changelog.

We have no control over the error message, that comes from Linux. The fact that we changed how executable files are handled is listed in the changelog:

The reloader will not prepend the Python executable to the command line if the Python file is marked executable. This allows the reloader to work on NixOS. #1242

Making the file not executable works. The shebang line does not, for me. I get file not found errors, instead. That was the first thing I tried.

With #!/usr/bin/env python3 :

I also think making a change that works only on one Linux distribution but breaks the rest doesn’t seem ideal. Making the files not executable seems like the proper solution, but this still feels broken to me.

@penner42 try #!/usr/bin/env python

probably you don’t have symlink on python3

Same result. The python3 symlink is there, and just running /usr/bin/env python3 or /usr/bin/env python from a shell works.

FWIW, Docker does gives this warning when building.
SECURITY WARNING: You are building a Docker image from Windows against a non-Windows Docker host. All files and directories added to build context will have ‘-rwxr-xr-x’ permissions. It is recommended to double check and reset permissions for sensitive files and directories.

Use the flask run command.

Did the tutorial at https://docs.docker.com/compose/gettingstarted/ used to work on Windows 7?
Is this recent change the cause why I see a similar error trying to run the example:

Did the same tutorial and found the same issue. This fixed it for me.

I added the following shebang to the top of my app.py script

Which then caused permission issues. I then added the following to my Dockerfile before the CMD

Источник

python3.8 aarch64 linux platform LpProblem.solve has error OSError: [Errno 8] Exec format error #433

Details for the issue

What did you do?

In my program I called
prob=LpProblem(«binPack», 1)
prob += some constraints
prob.solve(PULP_CBC_CMD(maxSeconds=tmlim, fracGap=mipgap, msg=1, keepFiles=0))

What did you expect to see?

What did you see instead?

The info below often helps, please fill it out if you’re able to. 🙂

What operating system are you using?

• Windows: ( version: ___ )
• [x ] Linux: ( distro: ___ )
• Mac OS: ( version: ___ )
• Other: ___

I’m using python version:

• 2.7
• 3.4
• 3.5
• 3.6
• [x ] Other: 3.8___

I installed PuLP via:

• [x ] pypi (python -m pip install pulp)
• github (python -m pip install -U git+https://github.com/coin-or/pulp)
• Other: ___ (conda?)

Did you also

• [x ] Tried out the latest github version: https://github.com/coin-or/pulp
• [x ] Searched for an existing similar issue: https://github.com/coin-or/pulp/issues?utf8=%E2%9C%93&q=is%3Aissue%20

The text was updated successfully, but these errors were encountered:

Hello!
Try to check this page for ways to debug and found the root cause: https://coin-or.github.io/pulp/guides/how_to_debug.html

Specially, try to see if you have the rights to execute cbc from that environment:

Specially, try to see if you have the rights to execute cbc from that environment:

Hi, I haved checked the file PATH_TO_PULP/solverdir/cbc/linux/64/cbc, it is in x_86-64 format, so it cannot be run. But here still have a problem, is pulp supported to install on aarch64 platform? Because I pip install it on a aarch64 machine but got a x86 cbc file.

I had no idea what the aarch64 platform is. Googling leads to ARM architecture. The binaries that come with PuLP are most probably not suited for that (they are pre-compiled executables). PuLP itself works but you have to look for your own solver binaries (cbc or any other).

Источник

1. Recreate OSError: [Errno 8] Exec format error in Linux
2. Add #!/bin/sh to Fix OSError: [Errno 8] Exec format error in Linux
3. Use sh to Fix OSError: [Errno 8] Exec format error in Linux

The subprocess module in Python allows you to run commands by creating new processes. When running a shell script using its methods, sometimes you may get an OSError: [Errno 8] Exec format error in Linux.

The problem Exec format error is raised when the script is directly run and not through the correct interpreter. It occurs if there is no shebang line at the beginning of the script file.

This tutorial will teach you to fix Linux’s OSError: [Errno 8] Exec format error.

Recreate OSError: [Errno 8] Exec format error in Linux

First, let’s recreate OSError: [Errno 8] Exec format error in Linux.

The following is a Bash script myshell.sh that returns Welcome to DelftStack Tutorials.

echo "Welcome to DelftStact Tutorials"

Below is a Python script, myscript.py, that runs the above script using subprocess.Popen().

import subprocess
shell_file = '/home/delft/myshell.sh'
P = subprocess.Popen(shell_file)

Run the Python script in the terminal.

python3 script.py

Output:

Traceback (most recent call last):
  File "myscript.py", line 3, in <module>
    P = subprocess.Popen(shell_file)
  File "/usr/lib/python3.8/subprocess.py", line 858, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "/usr/lib/python3.8/subprocess.py", line 1704, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
OSError: [Errno 8] Exec format error: '/home/delft/myshell.sh'

As you can see, it returns the error OSError: [Errno 8] Exec format error.

Add #!/bin/sh to Fix OSError: [Errno 8] Exec format error in Linux

The best way to solve this issue is by adding #!/bin/sh at the top of the shell script file myshell.sh. It ensures that the system uses the right interpreter to run the .sh script.

Edit the myshell.sh file with any editor and add the below lines.

#!/bin/sh
echo "Welcome to DelftStack Tutorials"

Now run the Python script to see the result.

python3 myscript.py

Output:

Welcome to DelftStack Tutorials

Use sh to Fix OSError: [Errno 8] Exec format error in Linux

You can also specify sh in Python script in the command that runs the shell script file.

Here is an example of it.

import subprocess
shell_file = '/home/delft/myshell.sh'
P = subprocess.Popen(['sh', shell_file])

Next, run the Python script file.

python3 myscript.py

Output:

Welcome to DelftStack Tutorials

Now you know how to solve OSError: [Errno 8] Exec format error and run shell scripts using Python in Linux. We hope you find this tutorial helpful.

Python doesn’t need an introduction as it is an integral part of programming that every programmer as well as a beginner is aware of. It has given the liberty to programmers all over the world to develop any application they want according to their set of rules. As it is the most used language, it is obvious to experience errors. Beginners often get worried when they see an error message pop up. You may encounter the error ‘Oserror: [errno 8] exec format error’ that makes you wonder what you have done to get the error warning.

You should not be worried as there is no such error that can’t be fixed. As you came here to get the error resolved, we help you with the solutions that you can simply implement. But before reach to the solution sections, let’s check out how the error occurs

How do you get the error?

When you are using subprocess.Popen for the arguments being parsed. You must be having a tough time executing the code on the Unix server. Have a look at the code

import subprocess
 Out = subprocess.Popen(['/usr/local/bin/script', 'hostname = ', 'actual server name', '-p', 'LONGLIST'],shell=True,stdout=subprocess.PIPE,stderr=subprocess.PIPE)

You end up with the error warning as soon as you import. This is what you get in return

OSError: [Errno 8] Exec format error

Now that you have seen how the error occurs, check out the solution to fix the error

Solutions to Fix ‘Oserror: [errno 8] exec format error’

The error happens because of many errors when you are running a Python script on a Unix server.  The prominent cause of the error is the shebang line’s absence. We have solutions to handle the exception in a simpler way. Have a look at the solutions to fix it

Solution 1 – Add Shebang line

The error pops up when there is no shebang line at the top of the shell script. You may not get any error when running the command in the shell. But the subprocess.check output() can’t just execute or run the shell by default.

Use the following ways to handle the exception

• At the start of the faulty file or the command, add /bin/bash
• In the first line, you need to add the shebang #!/bin/sh

Have a look at the code

#python -c "import pexpect; p=pexpect.spawn('/bin/bash /usr/local/ssl/bin/openssl_1.1.0f version'); p.interact()"
OpenSSL 1.1.0f 25 May 2017

Solution 2 – Add Shebang line

This is another way to add the shebang line at the top of the shell script. If you run the script without the shebang line, you get the error message. Take a look at the example

>>> with open('a','w') as f: f.write('exit 0') # create the script
... 
>>> import os
>>> os.chmod('a', 0b111101101) # rwxr-xr-x make it executable 
>>> os.execl('./a', './a') # execute it 
Traceback (most recent call last):
 File "<stdin>", line 1, in <module>
 File "/usr/lib/python2.7/os.py", line 312, in execl
 execv(file, args)
OSError: [Errno 8] Exec format error

To fix it, add the shebang line. On the top of your shell script add #!/bin/sh. The code looks like this

>>> with open('a','w') as f: f.write('#!/bin/shnexit 0')
... 
>>> os.execl('./a', './a')

You will not see any error when executing exit 0

On the POSIX system, the command line is parsed by shell. No space around ‘=’ can be seen by the script of yours. In this case, the script is like this

#!/usr/bin/env python
import sys
print(sys.argv)

It runs in the shell like this:

$ /usr/local/bin/script hostname = '<hostname>' -p LONGLIST

And it produces the following code

['/usr/local/bin/script', 'hostname', '=', '<hostname>', '-p', 'LONGLIST']

In order to match the shell command in Python, you should run the following

from subprocess import check_call

cmd = ['/usr/local/bin/script', 'hostname', '=', '<hostname>', '-p', 'LONGLIST']
check_call(cmd)

Make the script in the correct order to avoid the error warning. Follow the below code

$ file /usr/local/bin/script

You can also compare the architecture using the below command

Conclusion

In this post, we have discussed two solutions to a similar problem to fix the error ‘Oserror: [errno 8] exec format error’. To add the shebang line, we highlighted two possible ways, you can choose that fit the best for you. I wish you luck!

Reference Source: https://www.solved.tips/oserror-errno-8-exec-format-error/

https://www.baeldung.com/linux/shebang