Android execute shell command and get output
However, I'm not aware of how I can get the output the command returns. I tried doing System. The execution of that command should return two numbers separated by a semicolon. How could I get this in a variable to print out? Read the Javadoc for more details here. ProcessBuilder would be a good choice to use. Besides using ProcessBuilder as suggested Senthil, be sure to read and implement all the recommendations of When Runtime.
Here is the example using ProcessBuilder with specifying environment variables and working folder for the command:. Processes have a limited buffer for stdout and stderr output. If you don't listen to them concurrently, one of them will fill up while you are trying reading the other. For example, you could be waiting to read from stdout while the process is waiting to write to stderr.
You cannot read from the stdout buffer because it is empty and the process cannot write to the stderr buffer because it is full. You are each waiting on each other forever. The key is to use ProcessBuilder. This allows you to read a single stream without having to alternate between stdout and stderr.
The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I want to write a function that will execute a shell command and return its output as a stringno matter, is it an error or success message.
I just want to get the same result that I would have gotten with the command line. The answer to this question depends on the version of Python you're using. The simplest approach is to use the subprocess. If you need to write input to stdinskip ahead to the run or Popen sections. If you're using Python 3. It provides a very general, high-level API for the subprocess module.
To capture the output of a program, pass the subprocess. PIPE flag to the stdout keyword argument. Then access the stdout attribute of the returned CompletedProcess object:. The return value is a bytes object, so if you want a proper string, you'll need to decode it. Assuming the called process returns a UTFencoded string:. If you want to pass input to the process's stdinpass a bytes object to the input keyword argument:. PIPE capture to result.
This adds just a bit of complexity, compared to the old way of doing things. But I think it's worth the payoff: now you can do almost anything you need to do with the run function alone. It has been available since Python 2. It takes takes the same arguments as Popen see belowand returns a string containing the program's output.
The beginning of this answer has a more detailed usage example. In Python 3. See the Popen examples below in that case. The Popen constructor accepts either a single command without arguments, or a list containing a command as its first item, followed by any number of arguments, each as a separate item in the list.
Popen objects also accept a host of different arguments for process IO management and low-level configuration. To send input and capture output, communicate is almost always the preferred method. As in:.
In some rare cases, you may need complex, real-time output capturing. Vartec 's answer suggests a way forward, but methods other than communicate are prone to deadlocks if not used carefully. That means no fancy bash-style pipes. However, doing so raises security concerns. If you're doing anything more than light scripting, you might be better off calling each process separately, and passing the output from each as an input to the next, via. The temptation to directly connect pipes is strong; resist it.
Otherwise, you'll likely see deadlocks or have to do hacky things like this. It's worth taking a moment to learn about unicode if you haven't already. For a solution that works in both Python2 and Python3, use the subprocess module instead:.GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together.
If nothing happens, download GitHub Desktop and try again. If nothing happens, download Xcode and try again. If nothing happens, download the GitHub extension for Visual Studio and try again. Download the latest AAR or grab via Gradle:. You can open multiple shell instances using Shell. Builder or Shell. Calling Shell. Skip to content. Dismiss Join GitHub today GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together.
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How to execute a command and get the output of command within C++ using POSIX?
Latest commit b6f Apr 25, Android Shell Execute shell commands on Android. Download the latest AAR or grab via Gradle: compile ' com. CommandResult Shell. You signed in with another tab or window. Reload to refresh your session.
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Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I have looked at using the system function, but that will just execute a command. Here's an example of what I'm looking for:.
I need to run an arbitrary command and get its output. I've looked at boost. Getting both stdout and stderr and also writing to stdin, not shown here is easy peasy with my pstreams header, which defines iostream classes that work like popen :. For Windows, popen also works, but it opens up a console window - which quickly flashes over your UI application.
If you want to be a professional, it's better to disable this "flashing" especially if the end-user can cancel it. On the off-chance that there is no popenyou can use system ". You can get the output after running a script using a pipe. We use pipes when we want the output of the child process.
So here is the script, which you want to run. Put it in a command variable with the arguments your script takes nothing if no arguments. So the popen runs your script and puts the output in fpipe and then you can just copy everything from that to your output file. So if we will put everything in a file while we run the command, you won't have to copy anything. In that case, there isn't any need to use pipes.
You can use just systemand it will run the command and put the output in that file. It was shown in documentation of std::system. Learn more. Ask Question. Asked 11 years, 2 months ago. Active 1 month ago. Viewed k times. Jonas Stein 5, 5 5 gold badges 34 34 silver badges 64 64 bronze badges.A "shell" is a program that listens to keyboard input from a user and performs actions as directed by the user. Android devices come with a simple shell program.
This shell program is mostly undocumented. Since many people are curious about it I thought I'd write up some documentation for it. The built-in shell has very limited error handling. When you type a command name incorrectly it will say "permission denied", even though the real problem is that it couldn't find the command:.
The PATH is a colon ':' seperated list of directories. You can find out what your shell's PATH is set to by using the built-in echo command:. Commands To find out what commands you have available to you, use the "ls" command on each of the directories in the PATH variable.
Many of the Android commands are based on standard Linux or bsd commands. If you're curious about a command, you can sometimes learn how it works by using the "man" command on a desktop Linux or OSX Apple Macintosh computer. The Linux or OSX version of the command may be different in details, but much of the documentation will still apply to the Android version of the command.
Another source of documentation for people without a Linux or OSX machine handy is to use a web browser and use a web search engine to search for the text: "man Linux command-name". The following is a list of the commands that are present on a Nexus S phone running an Android 2.
Many of these commands are not present on a "user" phone. They are missing from a "user" phone because they are specific to developing or debugging the Android operating system.
You can create this directory using the "mkdir" command if you like. You need root access. If you have a developer phone, or otherwise have root access to your phone you can see what's in this directory.
These files are from a Nexus S. It's used to start and stop Android activities e.In Java, we can use ProcessBuilder or Runtime. Example to execute shell command host -t a google. Later, we use regular expression to grab all the IP addresses and display it. I used the same similar code for my ShellWrapper. When I use commands like echo it works fine, but when I use commands like cat it returns an empty String…. See problematic frame for where to report the bug. Suggestion to try displaying a very simple message box first in dll in order to determine if you gui has the error and not the code.
If this works, then the problem is in your graphical window and not the dll or java. Please help me… java. Make sure your system has installed it. I have a similar error. I ran it on windows 7 and got same erroe message. How, sir, can I resolve the problem? ERROR: java. Do you even read the stack trace?!!! OS X is a Unix based system. Windows is not!!! The following code allows you to set a timer, restart the timer on keywords, and specify if you want it to be sent to your log or not.
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I want to execute some shell commands and get the output in a TextView. The command may have a continuous output like ping or logcat.
Also, the TextView should scroll automatically as the command output is added in real-time. In order to do so, I have done this:. This works fine, but it does not update the TextView continuously.
How to execute shell command from Java
As you can see, I'm executing radio logcat as root user, the output is generated continuously already checked in terminal emulator and adb shell. But in my case, the output is not added continuously. It stops after a few lines. Here is my layout:.
The output should keep scrolling the TextView. At least this is what I expect Any workaround for this please? Note : The "su" command does only run if the device is rooted. Otherwise it throws an exception. I think the problem is that you wait for 5s to start reading the output and when the program starts it reaches the end of the stream because it is faster than the speed the log is generated. Thus you need to wait again for some time and start reading the buffer again.
The following code works for me. Take this String function and store the result into your TextView or wherever you want. Learn more. Execute shell commands and get output in a TextView Ask Question. Asked 5 years, 11 months ago. Active 5 months ago. Viewed 12k times. In order to do so, I have done this: package com. DataOutputStream; import java. InputStream; import android. Activity; import android. Bundle; import android.