How to run rename shell command in android app (ro

问题:

I'm new to Android. I'm trying to run a shell command to rename a file in the system. I've got root access to it.

The shell command:

$ su
# mount -o remount,rw /system
# mv system/file.old system/file.new

I have tried this but doesn't work:

public void but1(View view) throws IOException{
    Process process = Runtime.getRuntime().exec("su");
    process = Runtime.getRuntime().exec("mount -o remount,rw /system");
    process = Runtime.getRuntime().exec("mv /system/file.old system/file.new");
}

回答1:

You can run more then one command using the same process, by writing the commands in the process's OuputStream. This way the commands will run in the same context that the su command is running. Something like:

Process process = Runtime.getRuntime().exec("su");
DataOutputStream out = new DataOutputStream(process.getOutputStream());
out.writeBytes("mount -o remount,rw /system\n");
out.writeBytes("mv /system/file.old system/file.new\n");
out.writeBytes("exit\n");  
out.flush();
process.waitFor();

回答2:

You need each command to be in the same process as su, since the switch to root doesn't apply to your application, it applies to su, which completes before you get to mount.

Instead, try two exec's:

...exec("su -c mount -o remount,rw /system");
...exec("su -c mv /system/file.old system/file.new");

Also, be aware that I've seen some systems where the mount -o remount,rw /system would fail however mount -o remount,rw /dev/<proper path here> /system would succeed. The "proper path here" is different from one manufacturer to the next, but it can be programatically gathered.