Structure and purpose of folders and files in Android/ - The root folder.
/ bin - folder containing executable files and links to executable files. Executable files are programs that run at system startup, as well as the most necessary programs that are accessible to all. Example: ls, mount, pwd, unzip.
/ data - a folder with data about synchronization and accounts, passwords to wifi access points and vpn settings, etc.
/ data / app - folder containing installed programs and games.
/ data / data - folder containing application data, their settings, game saves and other information.
/ data / dalvik-cach e is the program cache area for the Dalvik program. Dalvik is a Java virtual machine, which is the basis for the work of programs with * .apk extension. In order to make the launch of programs faster - their cache is created.
/ dev - a folder containing files of various devices, both real and virtual, as well as those devices that are not there, but which could be.
/ etc - folder containing the configuration files used when loading the operating system and in the process of various programs.
/ lib - a folder containing libraries of functions necessary for various programs and the C compiler, as well as modules (device drivers) connected to the kernel.
/ lib / modules / - a folder comprising modules (device drivers) of the core, which have the extension .ko. In this folder, the subfolders arranged that coincide with kernels (e.g., 2.6.32.9-default), which were installed in the system. That is, for each kernel version has its own set of modules. This is very important and you need to pay attention to it. Often when compiling the kernel to forget to change the version of the new boot kernel modules using the previous version and the system will not boot. The current version of the kernel can be found on command uname -r, returned version necessarily coincide with the name of one of the folders in the / lib / modules /.
/ mnt - contains folders for temporarily mounted file systems.
/ proc - a virtual folder containing all the details of the Android system, including the kernel, processes, and configuration parameters.
More details folder / proc
/ Proc - virtual file system that contains all the information about the Android system, including core processes, configuration parameters, hardware information. All files in the / proc are also virtual, and does not actually take place in the memory (so the size of the file is 0 bytes), the operating system creates them "on the fly" when a user tries to read them. Any manipulation in the folder / proc are only possible with root privileges. / Proc file system can be viewed as an interface to the internal data structures in the Android kernel. This interface allows you to obtain information about the system and change some parameters to the kernel at the time of the Android operating.
Many programs collect information from files in / proc, format them and output the result to the user (top, ps and others). There is a special folder / proc / sys in the / proc file system. It allows you to view kernel parameters and change these parameters on the fly without rebooting the system.
The virtual system / proc files are not intended to be viewed with a regular text editor, as this may violate the integrity of the kernel data. To do this, use the echo and cat commands.
/ proc / nnnn - virtual folders with numbers correspond to each process running in the system.
/ proc / net is a virtual folder containing information about networks.
/ proc / net / dev is a virtual file containing information about each network device.
/ proc / sys is a virtual folder containing kernel configuration parameters.
/ proc / meminfo is a virtual file containing memory information (to view this information, type the following command: cat / proc / meminfo).
/ proc / version - a virtual file containing information about the Android kernel version (cat / proc / version command).
/ proc / cmdline is a virtual file containing information about the parameters passed to the kernel during the boot (command cat / proc / cmdline).
/ proc / cpuinfo is a virtual file containing information about the processor.
/ proc / loadavg - a virtual file containing information about the average processor load; its information includes: CPU utilization in the last minute, in the last 5 minutes, and in the last 10 minutes, as well as the number of current processes.
/ proc / stat is a virtual file containing information about statistics related to the previous system load.
/ proc / uptime is a virtual file containing only two numbers: how many seconds the machine has been working and how many seconds it has been idle.
/ proc / devices - a virtual file containing information about all configured and loaded character and block devices at the moment.
/ proc / ioports is a virtual file containing information about input / output ports (I / O communications) used by devices.
/ proc / filesystems is a virtual file containing information about all file systems that are supported by the kernel.
/ proc / mounts is a virtual file containing information about all mount points used in the device.
/ proc / partitions is a virtual file containing information about all sections.
/ proc / swaps is a virtual file containing information about all swap spaces (swap space).
/ sbin - folder containing executable files of programs that are designed to manage the system itself. Example: ifconfig, man, mdev, vconfig.
/ sdcard - a folder containing files and folders on the SD memory card (if installed).
/ sys folder containing the actual system configuration at the current time. / sys is very closely related to udev if you connect (disconnect) devices, the contents of the / sys directory change dynamically. You can look at an example. Run the ls / sys / bus / usb / devices / command to view the current usb devices in the system. Now connect the flash drive and execute the command ls / sys / bus / usb / devices / again. You will see that now there are more devices.
/ system - a folder containing system files and folders with data and everything necessary for the operation of the Android OS.
/ system / app - a folder containing system applications (SMS, phone, calendar, settings, etc.), as well as applications installed by the device manufacturer (branded widgets, live wallpapers, etc.).
/ system / fonts - folder with system fonts.
/ system / media - a folder containing standard melodies of calls, notifications, alarms and interface sounds, as well as boot animation (bootanimation).
/system/build.prop - a file containing a huge number of settings, such as the density of the screen, the delay time of the proximity sensor, the wifi control, the name and manufacturer of the device, and many other parameters.
Now in firmware 4.4 some of the "main" system applications have been moved to the folder
/ priv-app (Calendar, Contacts, Settings, SystemUI)