[Solved] Mount a blank.img formated to ext? to bypass permission limitations? - Sprint Samsung Galaxy S III

I was wondering if I could mount an empty.img file so that I could add executable into it and chmod 777 them or what ever the number is maybe 666.
Then I would add the location to my $PATH variable in the "/system/etc/mkshrc" file so I could execute those programs from any directory.
What say you?
Has this been done before?

It works!
Well, I wen ahead and tried it out, I figured "What the hell, its not like I have to format my sd card." It worked!
So what I did
1) I changed directories to Downloads. ("cd ~/Downloads")
2) I created a directory for my image in Downloads, and moved into it. (mkdir image && cd ./image)
3) I created an empty 4 gig image called apps.img using dd ("dd if=/dev/zero of=apps.img bs=1MB count=0 seek=4096")
4) I formated it to ext2 ("mke2fs -F apps.img")
5) I used adb to push it to my phone ("adb push ~/Downloads/image/apps.img /storage/sdcard0/Download/")
6) Then on my phone as su I mounted the image ("mount -o loop '/storage/sdcard0/Download/apps.img' '/data/local/mnt' ") {with single quotes around the directories, the double quotes wrap the whole actual command, you don't need them} [EDIT: I used bash on the phone to do this, ie I "su" [enter] ; "bash" [enter] ; "THE ABOVE COMMAND" [enter]
7) To test I used the python interpreter as my executable so I created a folder in /data/local/mnt called apps,(note* I should have made that folder on my pc before I pushed it to my phone to ensure that the foder was actually in the apps.img file.) I created two more folders "bin" and "lib" using "File Manager" on my phone. I then moved what I needed to run python into those folders (though you'll see I forgot something)
8) I added PYTHONHOME PYTHONPATH and added the bin folder I created to $PATH in the /system/etc/bash/bashrc file (Ask and I'll explain). If you don't have bash the mkshrc file is located "/system/etc/mkshrc" on your phone (if its Sprint SGSIII) adding environment variable there will accomplish the same thing, sorta.
9) I connected my phone to pc w/usb, opened up a teminal on pc, started an adb shell
10)........
Code:
[email protected]:~$ adb devices
List of devices attached
xxxxxxxx device
[email protected]:~$ adb shell
[email protected]:/ $ su
[email protected]:/ # bash
void endpwent()(3) is not implemented on Android
localhost / # which python
/data/local/mnt/apps/bin/python
localhost / # python
'import site' failed; use -v for traceback
Python 2.6.2 (r262:71600, Mar 20 2011, 16:54:21)
[GCC 4.4.3] on linux-armv7l
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>> import sys
>>> import math
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: No module named math
>>> import io
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/home/manuel/AptanaStudio3Workspace/python-for-android/python-build/output/usr/lib/python2.6/io.py", line 63, in <module>
ImportError: No module named _fileio
>>>
localhost / # exit
[email protected]:/ # ^D
[email protected]:/ $ ^D
[email protected]:~$

I'm thinking that if I can get my mkbootimg tools to work, I would mod an init script to mount the apps.img and then create links for each file in say '/mnt/apps/bin' create a link*in '/system/bin'. this should allow for phones with small or near full system partition install stuff like busybox or your own pprograms. More usefull for a developer.
I wanna try this with pythonforandroid, if I can make python and its modules. accessible during early init or just before the boot process finishes in general, and use it to run python, maybe python can handle boot in a different way, or maybe just one specific. function you might needs.
one big question I have. Does the pythonforandroid interpreter run ontop of the D VM?

Edge-Case said:
I'm thinking that if I can get my mkbootimg tools to work, I would mod an init script to mount the apps.img and then create links for each file in say '/mnt/apps/bin' create a link*in '/system/bin'. this should allow for phones with small or near full system partition install stuff like busybox or your own pprograms. More usefull for a developer.
I wanna try this with pythonforandroid, if I can make python and its modules. accessible during early init or just before the boot process finishes in general, and use it to run python, maybe python can handle boot in a different way, or maybe just one specific. function you might needs.
one big question I have. Does the pythonforandroid interpreter run ontop of the D VM?
Click to expand...
Click to collapse
I don't think so. All command-line programs I know of interface directly with the kernel.
Sent from my S3 on Sense 5 (you jelly?)

CNexus said:
I don't think so. All command-line programs I know of interface directly with the kernel.
Sent from my S3 on Sense 5 (you jelly?)
Click to expand...
Click to collapse
So getting an extended set of Linux (kernel) cli programs working with Android (kernel) is a matter of having the nessissary libraries, kernel prereq., and being compiled for the target processor?
From what I have read, the Android kernel has been cut back so far from the original Linux kernel that its difficult to port "Linux apps" to Android. Something about a slimmed down version of the GNU C/C++ libraries and the Android kernel being designed to run mostly Dalvik.
I haven't tried directly running any "Linux app" (already compiled for arm) on Android yet, but my game plan for that test was to load up an .img file with the nessissary execs, libs, config, etc files (as ext3 this time) and running some scripts that get the paths variables set up and then execute the script, I wrote a short Bash script that sets up python variables and adds others to PATH etc, and it worked, I had python on the img and the img mounted to /mnt/myside and python ran but with some errors, I need to get the variables right, its driving me mad, if its not this its that, last time it was the basic "help()" command not being declaired or something.
Well thats my plan, either these "Linux apps" run on Android without problem or I am going to A) write my own kernel to be compatible with Android/ cli Linux or I am going to get as much source code as I can and practice the art of compiling against Android and/or patching the code when/where nessissary.
We'll see what happens, I've done enough today/night.

Related

[SCRIPT] changelist - Firmware changelist generator

I've created a small *nix shell script which tries to generate a nicely formatted list of changes between the /system portion of two firmwares. It also produces a 'diff' file containing the changes between text files it encounters.
It tries to present the information in a compact way, keeping the most pertinent information (like changes in build.prop/default.prop) on top. File changes are grouped together by directory, again keeping additions and deletions on top, followed by modifications.
You can see some example output in this thread
The script requires a few utilities to be available: grep, fmt, diff, filterdiff and interdiff.
grep and fmt are probably available on any *nix system, diff is part of the basic development package set.
filterdiff and interdiff are part of the 'patchutils' package in Debian and Ubuntu.
On Ubuntu you can install the dependencies with:
$ sudo apt-get install diffutils patchutils
To use the changelist script, simply run it with two directories into each of which you have extracted a factoryfs.rfs from the corresponding firmware, e.g.:
$ # Extract I9000XWJPI's factoryfs.rfs into I9000XWJPI/system
$ # Extract I9000XWJS3's factoryfs.rfs into I9000XWJS3/system
$ # then run
$ ./changelist I9000XWJPI I9000XWJS3
The script will produce two output files in the current directory, in this example they are:
I9000XWJPI-I9000XWJS3.txt (containing the formatted changelist)
I9000XWJPI-I9000XWJS3.diff (containing the textual changes in 'diff' format)
I hope you like it, please post any suggestions, bugfixes etc., in this thread.

[TUTORIAL] Everything about ADB - A reference for everyone

TUTORIAL - EVERYTHING ABOUT ADB - Fully Illustrated
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This will be part of a series of Tutorials compiled to better educate the Beginner-Intermediate users in XDA thread, and help them get rid of the "n00b" or "newbie" tag thrown at them!
1. WHAT IS ADB?
ADB or Android Debug Bridge is a command line program which is used to communicate with your Android phone (or an emulator used by programmers). The use of Adb for Android phone users ranges from using it as a tool to get the logcat- A realtime log of the Android system, which allows one to know the cause of any errors. It is very helpful to app hackers to know exctly what block of code does what, and to modify apps accordingly
2. HOW TO USE ADB - Running adb.exe
adb.exe is part of a package of tools called Android SDK or Software Development Kit. For users, the main applications useful for them are adb.exe, fastboot.exe and aapt.exe.
2.1 Installing adb.exe (Windows)
First, download the Android SDK package(exe file) from here The installer will prompt you to download and install the JDK (Java Development Kit) if you dont have it already installed
Next install the exe file and note the location where you install it to.
After install is over, use Windows explorer and navigate to the folder where you installed the SDK.
Double-click the SDK Manager.exe/SDK Setup.exe file at the root of the Android SDK directory.
This will open up the SDK Installation window, where you can choose from a list of packages to install
If you want to use only adb.exe and fastboot.exe, choose to install only the "Android SDK Tools" from the list (See fig 1 below)
That's it, adb.exe is now installed
Fig1:
Take a note of where you install it. It usually installs to a folder named Android-sdk-windows. Once you have it installed, you can copy the entire folder on a portable usb key/CD and use it on any other PC without a need to install it. I recommend that you make it a part of your Android CD (with rooting tools, unrooting tools, gold card etc).
2.2 Using adb.exe-Preparing your PC for running adb.exe quickly
Adding Adb to your Windows Path
Once installed, you should add the location of adb.exe to the* Windows Environment Path variable. To do that, go the subfolder of Android-sdk-windows where adb.exe can be found. Click on the Windows Explorer path displayed on Top, and copy the path to the Clipboard
Go to Start Menu, and Right click Computer, Choose Properties
Choose Advanced System Settings and then Environment variables
Now, add the Location you copied to the Clipboard earlier, to the end of the current path, after adding a ";"(without the quotes) to the end of the current path.
So, in my case, the current path shows:
c:\droidzone\windows; c:\droidzone\blahblah
It now becomes:
c:\droidzone\windows; c:\droidzone\blahblah;C:\Software\Phone\android-sdk-windows\tools
Hit Enter to everything.
From now, whenever you open a Command prompt in Windows, you will be able to execute Adb and Fastboot from there without needing to navigate to the folder where they are installed.
Next step: Elementary Adb commands
Don't forget to Hit the Thanks button to let me know that my posts helped you!
Elementary Adb commands
Ok, now that you've got adb all setup and prepared your computer to use it, you're ready to learn some basic adb commands. I'll be teaching some of them in this section.
Understanding how adb and the shell works
Let's first check if adb is working by asking it to communicate with our phone. Connect the phone with a usb cable to the PC. Note that you should have installed the HTC drivers already (They come with HTC Sync)
From your Windows Start Menu, Click on Run, then type the following and press enter. That should open a command shell:
Code:
cmd
Once there, type out the following:
Code:
adb devices
This will display a list showing the connected phones with their serial numbers (and emulators-But let us not worry about what these are, right now)
Great, now we have confirmation that adb is working! We're now ready to issue our basic commands.
First thing to note is the basic command to enter the Android custom linux shell. Like Windows has cmd.exe to enter the dos shell, the graphical eyecandy with Sense overlay that you see on your device has a custom linux kernel running, so basically the language of its shell is the Linux shell language.
Accessing the Linux terminal (adb shell) is what we do to issue commands. To enter the shell of our device, the basic command is:
Code:
adb shell
Immediately, you will get a prompt like this:
Code:
sh-3.2#
Now we can type out any (most) linux commands and these will be executed in our device.
The file system on Android is laid out over MTD partitions in your device's NAND (Internal memory), and the SD card. The Nand is strictly organized in a Linux system with Linux file permissions and ownership rights (Just know that these exist, for now)
So, right now, you will be dropped in the "root" of the filesystem, from where you can navigate to other places.
Note! An important difference between Linux and Windows is that while Windows uses the Backslash (\), Linux/Android uses the forward slash (/) to depict directory hierarchies. Another one you shouldnt forget is that in Linux/Android, a file named boot.img is different from Boot.img, BOOT.IMG and BoOt.img, while on Windows, they are all the same.
Click to expand...
Click to collapse
My tutorial is about adb commands, and not linux, so I'll give only a short summary of elementary linux commands below. I will expand the list and explanation for this at a later date if you require it:
pwd-Shows the current working directory
cp-copy a file
mv-move a file (copy a file and then delete the original file)
chmod-set file permissions
chown-set file ownerships
rm-delete a file
cd-change directory
rmdir-delete a directory
Click to expand...
Click to collapse
Elementary Adb commands
Installing applications with adb
You can install any apk from your PC to the phone very easily. Open a cmd shell, and then type in:
Code:
adb install
followed by a space. Now drag an apk file in Windows explorer to the shell we have opened. Immediately, the path of the file becomes inserted in our prompt that it becomes:
Code:
adb install C:\Desktop\TitaniumBackup.apk
assuming that the file TitaniumBackup.apk was present in the location C:\Desktop. Hit enter and you will notice that it gets installed.
Transferring files to the sdcard without connecting the device as Disk drive:
Code:
adb push C:\Desktop\TitaniumBackup.apk /sdcard/
will trasfer the file C:\Desktop\TitaniumBackup.apk to the root (main) directory of your sdcard. Likewise, you can transfer any file from the PC to any location on your device.
Eg: I want to transfer a file called wallpaper.zip to a location /data/local. The command would be:
Code:
adb push C:\Desktop\wallpaper.zip /data/local/
Contd..
Don't forget to Hit the Thanks button to let me know that my posts helped you!
More elementary adb commands:
Getting a file from your phone to your PC:
To get a file /system/etc/init.d/01data to your PC, you would type out the following:
Code:
adb pull /system/etc/init.d/01data
which will transfer the spcified file to the location on your pc where you have opened the cmd.exe shell.
Mounting the system partition as Read Write to transfer files to your /system partition:
Method 1:
Code:
adb remount
Method 2:
This can also be accomplished with the more advanced mount command in the adb shell. First we need to know the mount point of the partitions.
Type:
Code:
adb shell
mount
For me, it displays:
Code:
rootfs / rootfs rw,relatime 0 0
tmpfs /dev tmpfs rw,relatime,mode=755 0 0
devpts /dev/pts devpts rw,relatime,mode=600 0 0
proc /proc proc rw,relatime 0 0
sysfs /sys sysfs rw,relatime 0 0
/sys/kernel/debug /sys/kernel/debug debugfs rw,relatime 0 0
none /acct cgroup rw,relatime,cpuacct 0 0
tmpfs /mnt/asec tmpfs rw,relatime,mode=755,gid=1000 0 0
tmpfs /mnt/obb tmpfs rw,relatime,mode=755,gid=1000 0 0
tmpfs /app-cache tmpfs rw,relatime,size=8192k,mode=755,gid=1000 0 0
none /dev/cpuctl cgroup rw,relatime,cpu 0 0
[B]/dev/block/mtdblock3 /system yaffs2 ro,relatime 0 0[/B]
/dev/block/mtdblock4 /cache yaffs2 rw,nosuid,nodev,relatime 0 0
/dev/block/mtdblock5 /system/data yaffs2 rw,nosuid,nodev,noatime,nodiratime 0 0
/dev/block/mmcblk0p2 /data ext4 rw,nosuid,nodev,noatime,nodiratime,commit=50,bar
rier=0,stripe=64,data=ordered,noauto_da_alloc 0 0
/dev/block/vold/179:1 /mnt/sdcard vfat rw,dirsync,nosuid,nodev,noexec,relatime,u
id=1000,gid=1015,fmask=0702,dmask=0702,allow_utime=0020,codepage=cp437,iocharset
=iso8859-1,shortname=mixed,utf8,errors=remount-ro 0 0
/dev/block/vold/179:1 /mnt/secure/asec vfat rw,dirsync,nosuid,nodev,noexec,relat
ime,uid=1000,gid=1015,fmask=0702,dmask=0702,allow_utime=0020,codepage=cp437,ioch
arset=iso8859-1,shortname=mixed,utf8,errors=remount-ro 0 0
tmpfs /mnt/sdcard/.android_secure tmpfs ro,relatime,size=0k,mode=000 0 0
sh-3.2#
Note that the entry for system partition shows:
/dev/block/mtdblock3 /system yaffs2 ro,relatime 0 0
The ro means that /system is mounted as RO-i.e Read Only. The whole line means that the Nand MTD block device on /dev/block/mtdblock3 is mounted on the mount point /system, to use technical jargon.
We need to mount it as RW (Read Write)
The command is:
Code:
mount -o rw,remount /dev/block/mtdblock3 /system
This essentially mounts the /system as Read Write so that you can write to it (Normally you cant write to the /system partition), which is what "adb remount " also does. However the commands above can be executed from a Terminal Emulator application too.
Next: Getting an Adb logcat
Don't forget to Hit the Thanks button to let me know that my posts helped you!
Getting an adb logcat
Many a time, you might have heard people telling you to get a logcat to report your error with a Rom installation.
What is a logcat?
A logcat is a report from the Android logging system, which takes place in the background the whole time your phone is on. It starts the moment you switch on the phone, and continues till you shut it down completely. This log is extremely useful for finding out what went wrong with your system. It is useful to find out why your phone is having bootloops or force closes. It is infact useful for all errors!
How to get the logcat?
Basically, you can view the logcat log with the following command:
Code:
adb logcat
But that means getting overwhelmed by an endless haze of output flowing at a rate that you cant read and will overwhelm your command shell's capacity very soon.
So the system we normally use is to output the log to a file from which we can read later. This is done by the following command:
Code:
adb logcat > log.txt
My Technique
As a Rom developer and apk patcher, I have to constantly check for errors in my system. So I've devised an ingenous method to easily log logcat, and view them readily. I use a combo of commands executed in succession:
Code:
adb kill-server
echo "" > log.txt
start log.txt
adb logcat > log.txt
These commands essentially create a blank file named log.txt in the same path as the command shell you've opened. Then, it opens the file log.txt (which is blank at this point of time. Then it logs logcat output to that file. Once you refresh the opened file, it will show the output of logcat to this point of time. Refresh it once again, and it updates once more. You should install Notepad++ and associate .txt files with it, to get best results.
Instead of executing these four commands, you can download the batch file getlog.cmd and extract it from the zip file to the folder containing adb.exe. Once you type in the following command (from anywhere in Windows), you will achieve the same result as typing the four commands as above! Ingenious, eh?
Don't forget to Hit the Thanks button to let me know that my posts helped you!
Summary of other adb commands
The following is the partial list of commands supported by adb. You can obtain this list by the following command:
Code:
adb /?
Code:
C:\Users>adb /?
Android Debug Bridge version 1.0.26
-d - directs command to the only connected USB devic
e
returns an error if more than one USB device is
present.
-e - directs command to the only running emulator.
returns an error if more than one emulator is r
unning.
-s <serial number> - directs command to the USB device or emulator w
ith
the given serial number. Overrides ANDROID_SERI
AL
environment variable.
-p <product name or path> - simple product name like 'sooner', or
a relative/absolute path to a product
out directory like 'out/target/product/sooner'.
If -p is not specified, the ANDROID_PRODUCT_OUT
environment variable is used, which must
be an absolute path.
devices - list all connected devices
connect <host>:<port> - connect to a device via TCP/IP
disconnect <host>:<port> - disconnect from a TCP/IP device
device commands:
adb push <local> <remote> - copy file/dir to device
adb pull <remote> [<local>] - copy file/dir from device
adb sync [ <directory> ] - copy host->device only if changed
(see 'adb help all')
adb shell - run remote shell interactively
adb shell <command> - run remote shell command
adb emu <command> - run emulator console command
adb logcat [ <filter-spec> ] - View device log
adb forward <local> <remote> - forward socket connections
forward specs are one of:
tcp:<port>
localabstract:<unix domain socket name>
localreserved:<unix domain socket name>
localfilesystem:<unix domain socket name>
dev:<character device name>
jdwp:<process pid> (remote only)
adb jdwp - list PIDs of processes hosting a JDWP transport
adb install [-l] [-r] [-s] <file> - push this package file to the device and i
nstall it
('-l' means forward-lock the app)
('-r' means reinstall the app, keeping its data
)
('-s' means install on SD card instead of inter
nal storage)
adb uninstall [-k] <package> - remove this app package from the device
('-k' means keep the data and cache directories
)
adb bugreport - return all information from the device
that should be included in a bug report.
adb help - show this help message
adb version - show version num
DATAOPTS:
(no option) - don't touch the data partition
-w - wipe the data partition
-d - flash the data partition
scripting:
adb wait-for-device - block until device is online
adb start-server - ensure that there is a server running
adb kill-server - kill the server if it is running
adb get-state - prints: offline | bootloader | device
adb get-serialno - prints: <serial-number>
adb status-window - continuously print device status for a specifie
d device
adb remount - remounts the /system partition on the device re
ad-write
adb reboot [bootloader|recovery] - reboots the device, optionally into the boo
tloader or recovery program
adb reboot-bootloader - reboots the device into the bootloader
adb root - restarts the adbd daemon with root permissions
adb usb - restarts the adbd daemon listening on USB
adb tcpip <port> - restarts the adbd daemon listening on TCP on th
e specified port
networking:
adb ppp <tty> [parameters] - Run PPP over USB.
Note: you should not automatically start a PPP connection.
<tty> refers to the tty for PPP stream. Eg. dev:/dev/omap_csmi_tty1
[parameters] - Eg. defaultroute debug dump local notty usepeerdns
adb sync notes: adb sync [ <directory> ]
<localdir> can be interpreted in several ways:
- If <directory> is not specified, both /system and /data partitions will be u
pdated.
- If it is "system" or "data", only the corresponding partition
is updated.
I will add notes for these if you require them.
See the next post for Kernel errors..
How to get Kernel error messages
You can get debug messages from a running kernel with:
Code:
adb shell
dmesg
If you have reboots due to kernel panic, you should make users capture the last_kmsg log from /proc immediately on the reboot.
Note that dmesg can be disabled by the kernel maintainer, and hence some roms/kernels may not support the command.
Code:
adb shell
cat /proc/last_kmsg > /sdcard/last_kmsg
Should be done immediately after the reboot..Otherwise it will just get overwritten by newer kernel message.
So in brief, if you'd like to look at what the kernel is doing right now (any errors etc), you should use dmesg. If you want to know why your kernel rebooted, use the file proc/last_kmsg
It's extremely useful!
Don't forget to Hit the Thanks button to let me know that my posts helped you!
Guys, part of the tutorial is over.. Hope it is helpful. Will add more useful and advanced stuff later.. Hope it helps the newbies and some more seasoned users.
Feel free to ask any doubt that you think is silly, without fear of being ridiculed or being asked to search the thread! It should be related to adb though!
Impressive tutorial. You'll get my thanks when im back at my home pc
Sent from my HTC Desire S using XDA App
Nice tutorial bro. shoud be on dev section...???
coolexe said:
Nice tutorial bro. shoud be on dev section...???
Click to expand...
Click to collapse
Thanks bro.. I thought that might scare away newbies, plus since I havent done any actual development..
Droidzone said:
Thanks bro.. I thought that might scare away newbies, plus since I havent done any actual development..
Click to expand...
Click to collapse
Hi,
there is lots of thread in dev. section which doesn't belong to development...anyway nice tutorial for noobs...if possible add QtADB tool...
EDIT: Added to my threads
Will add a GUI section. Good tip.. It's a very useful tool
Hi there.
Well this is a nice tut for android newbies like me
can you also add a basic symlinking tut? (especially how to symlink a folder to an already existing symlink )
thanks!
jesseuy said:
Hi there.
Well this is a nice tut for android newbies like me
can you also add a basic symlinking tut? (especially how to symlink a folder to an already existing symlink )
thanks!
Click to expand...
Click to collapse
Does this answer your query?
From http://uw714doc.sco.com/en/SDK_sysprog/_Using_Symbolic_Links.html
Code:
[B]Creating symbolic links[/B]
To create a symbolic link, the new system call [URL="http://uw714doc.sco.com/en/man/html.2/symlink.2.html"]symlink(2)[/URL] is used and the owner must have write permission in the directory where the link will reside. The file is created with the user's user-id and group-id but these are subsequently ignored. The mode of the file is created as 0777.
CAUTION: No checking is done when a symbolic link is created. There is nothing to stop a user from creating a symbolic link that refers to itself or to an ancestor of itself or several links that loop around among themselves. Therefore, when evaluating a pathname, it is important to put a limit on the number of symbolic links that may be encountered in case the evaluation encounters a loop. The variable MAXSYMLINKS is used to force the error ELOOP after MAXSYMLINKS symbolic links have been encountered. The value of MAXSYMLINKS should be at least 20.
To create a symbolic link, the ln command is used with the -s option (see [URL="http://uw714doc.sco.com/en/man/html.1/ln.1.html"]ln(1)[/URL]). If the -s option is not used and a user tries to create a link to a file on another file system, a symbolic link will not be created and the command will fail.
The syntax for creating symbolic links is as follows:
ln -s sourcefile1 [ sourcefile2 ... ] target With two arguments:
[LIST]
[*] sourcefile1 may be any pathname and need not exist.
[*] target may be an existing directory or a non-existent file.
[*] If target is an existing directory, a file is created in directory target whose name is the last component of sourcefile1 (`basename sourcefile1`). This file is a symbolic link that references sourcefile1.
[*] If target does not exist, a file with name target is created and it is a symbolic link that references sourcefile1.
[*] If target already exists and is not a directory, an error is returned.
[*] sourcefile1 and target may reside on different file systems.
[/LIST]
With more than two arguments:
[LIST]
[*] For each sourcefile, a file is created in target whose name is sourcefile or its last component (`basename sourcefile`) and is a symbolic link to sourcefile.
[*] If target is not an existing directory, an error is returned.
[*] Each sourcefile and target may reside on different file systems.
[/LIST]
[B]Examples[/B]
The following examples show how symbolic links may be created.
ln -s /usr/src/uts/sys /usr/include/sys In this example /usr/include is an existing directory. But file sys does not exist so it will be created as a symbolic link that refers to /usr/src/uts/sys. The result is that when file /usr/include/sys/x is accessed, the file /usr/src/uts/sys/x will actually be accessed. This kind of symbolic link may be used when files exist in the directory /usr/src/uts/sys but programs often refer to files in /usr/include/sys. Rather than creating corresponding files in /usr/include/sys that are hard links to files in /usr/src/uts/sys, one symbolic link can be used to link the two directories. In this example /usr/include/sys becomes a symbolic link that links the former /usr/include/sys directory to the /usr/src/uts/sys directory.
ln -s /etc/group . In this example the target is a directory (the current directory), so a file called group (`basename /etc/group`) is created in the current directory that is a symbolic link to /etc/group. ln -s /fs1/jan/abc /var/spool/abc In this example we imagine that /fs1/jan/abc does not exist at the time the command is issued. Nevertheless, the file /var/spool/abc is created as a symbolic link to /fs1/jan/abc. Later, /fs1/jan/abc may be created as a directory, regular file, or any other file type. The following example illustrates the use of more than two arguments:
ln -s /etc/group /etc/passwd . The user would like to have the group and passwd files in the current directory but cannot use hard links because /etc is a different file system. When more than two arguments are used, the last argument must be a directory; here it is the current directory. Two files, group and passwd, are created in the current directory, each a symbolic link to the associated file in /etc. [B]Removing symbolic links[/B]
Normally, when accessing a symbolic link, one follows the link and actually accesses the referenced file. However, this is not the case when one attempts to remove a symbolic link. When the [URL="http://uw714doc.sco.com/en/man/html.1/rm.1.html"]rm(1)[/URL] command is executed and the argument is a symbolic link, it is the symbolic link that is removed; the referenced file is not touched.
[B]Accessing symbolic links[/B]
Suppose abc is a symbolic link to file def. When a user accesses the symbolic link abc, it is the file permissions (ownership and access) of file def that are actually used; the permissions of abc are always ignored. If file def is not accessible (that is, either it does not exist or it exists but is not accessible to the user because of access permissions) and a user tries to access the symbolic link abc, the error message will refer to abc, not file def.
[B]Copying symbolic links[/B]
This section describes the behavior of the [URL="http://uw714doc.sco.com/en/man/html.1/cp.1.html"]cp(1)[/URL] command when one or more arguments are symbolic links. With the [URL="http://uw714doc.sco.com/en/man/html.1/cp.1.html"]cp(1)[/URL] command, if any argument is a symbolic link, that link is followed. Suppose the command line is
cp sym file3 where sym is a symbolic link that references a regular file test1 and file3 is a regular file. After execution of the command, file3 gets overwritten with the contents of the file test1. If the last argument is a symbolic link that references a directory, then files are copied to that directory. Suppose the command line is
cp file1 sym symd where file1 is a regular file, sym is a symbolic link that references a regular file test1, and symd is a symbolic link that references a directory DIR. After execution of the command, there will be two new files, DIR/file1 and DIR/sym that have the same contents as file1 and test1.
[B]Linking symbolic links[/B]
This section describes the behavior of the [URL="http://uw714doc.sco.com/en/man/html.1/ln.1.html"]ln(1)[/URL] command when one or more arguments are symbolic links. To understand the difference in behavior between this and the [URL="http://uw714doc.sco.com/en/man/html.1/cp.1.html"]cp(1)[/URL] command, it is useful to think of a copy operation as dealing with the contents of a file while the link operation deals with the name of a file.
Let us look at the case where the source argument to ln is a symbolic link. If the -s option is specified to ln, the command calls the symlink system call (see [URL="http://uw714doc.sco.com/en/man/html.2/symlink.2.html"]symlink(2)[/URL]). symlink does not follow the symbolic link specified by the source argument and creates a symbolic link to it. If -s is not specified, ln invokes the [URL="http://uw714doc.sco.com/en/man/html.2/link.2.html"]link(2)[/URL] system call. link follows the symbolic link specified by the source argument and creates a hard link to the file referenced by the symbolic link.
For the target argument, ln invokes a stat system call (see [URL="http://uw714doc.sco.com/en/man/html.2/stat.2.html"]stat(2)[/URL]). If stat indicates that the target argument is a directory, the files are linked in that directory. Otherwise, if the target argument is an existing file, it is overwritten. This means that if the second argument is a symbolic link to a directory, it is followed, but if it is a symbolic link to a regular file, the symbolic link is overwritten.
For example, if the command line is
ln sym file1 where sym is a symbolic link that references a regular file foo, and file1 is a regular file, file1 is overwritten and hard-linked to foo. Thus a hard link to a regular file has been created.
If the command is
ln -s sym file1 where the files are the same as in first example, file1 is overwritten and becomes a symbolic link to sym. If the command is
ln file1 sym where the files are the same as in the first example, sym is overwritten and hard-linked to file1. When the last argument is a directory as in
ln file1 sym symd where symd is a symbolic link to a directory DIR, and file1 and sym are the same as in the first example, the file DIR/file1 is hard-linked to file1 and DIR/sym is hard-linked to foo. [B]Moving symbolic links[/B]
This section describes the behavior of the [URL="http://uw714doc.sco.com/en/man/html.1/mv.1.html"]mv(1)[/URL] command. Like the [URL="http://uw714doc.sco.com/en/man/html.1/ln.1.html"]ln(1)[/URL] command, [URL="http://uw714doc.sco.com/en/man/html.1/mv.1.html"]mv(1)[/URL] deals with file names rather than file contents. With two arguments, a user invokes the [URL="http://uw714doc.sco.com/en/man/html.1/mv.1.html"]mv(1)[/URL] command to rename a file. Therefore, one would not want to follow the first argument if it is a symbolic link because it is the name of the file that is to be changed rather than the file contents. Suppose that sym is a symbolic link to /etc/passwd and abc is a regular file. If the command
mv sym abc is executed, the file sym is renamed abc and is still a symbolic link to /etc/passwd. If abc existed (as a regular file or a symbolic link to a regular file) before the command was executed, it is overwritten. Suppose the command is
mv sym1 file1 symd where sym1 is a symbolic link to a regular file foo, file1 is a regular file, and symd is a symbolic link that references a directory DIR. When the command is executed, the files sym1 and file1 are moved from the current directory to the DIR directory so that there are two new files, DIR/sym1, which is still a symbolic link to foo, and DIR/file1. In UnixWare, the [URL="http://uw714doc.sco.com/en/man/html.1/mv.1.html"]mv(1)[/URL] command uses the [URL="http://uw714doc.sco.com/en/man/html.2/rename.2.html"]rename(2)[/URL] system call. If the first argument to [URL="http://uw714doc.sco.com/en/man/html.2/rename.2.html"]rename(2)[/URL] is a symbolic link, [URL="http://uw714doc.sco.com/en/man/html.2/rename.2.html"]rename(2)[/URL] does not follow it; instead it renames the symbolic link itself. In System V prior to Release 4, a file was moved using the [URL="http://uw714doc.sco.com/en/man/html.2/link.2.html"]link(2)[/URL] system call followed by the [URL="http://uw714doc.sco.com/en/man/html.2/unlink.2.html"]unlink(2)[/URL] system call. Since [URL="http://uw714doc.sco.com/en/man/html.2/link.2.html"]link(2)[/URL] and [URL="http://uw714doc.sco.com/en/man/html.2/unlink.2.html"]unlink(2)[/URL] do not follow symbolic links, the result of those two operations is the same as the result of a call to [URL="http://uw714doc.sco.com/en/man/html.2/rename.2.html"]rename(2)[/URL].
Thanks for adding the tut. Will be reading and will definitely try it out.
Thanks again!
Sent from my HTC Desire using XDA App
Thanks a lot for the tutorial. Basic stuff nicly explained. i tried the push method via adb to push a font into system/fonts directory still it says read only permission
C:\Users\Mayu>adb shell
# mount
mount
rootfs / rootfs ro 0 0
tmpfs /dev tmpfs rw,mode=755 0 0
devpts /dev/pts devpts rw,mode=600 0 0
proc /proc proc rw 0 0
sysfs /sys sysfs rw 0 0
none /acct cgroup rw,cpuacct 0 0
tmpfs /mnt/asec tmpfs rw,mode=755,gid=1000 0 0
tmpfs /mnt/obb tmpfs rw,mode=755,gid=1000 0 0
none /dev/cpuctl cgroup rw,cpu 0 0
/dev/block/mtdblock0 /system yaffs2 rw 0 0
/dev/block/mtdblock1 /data yaffs2 rw,nosuid,nodev 0 0
/dev/block/mtdblock2 /cache yaffs2 rw,nosuid,nodev 0 0
/dev/block/vold/179:0 /mnt/sdcard vfat rw,dirsync,nosuid,nodev,n
id=1015,fmask=0702,dmask=0702,allow_utime=0020,codepage=cp437,io
1,shortname=mixed,utf8,errors=remount-ro 0 0
/dev/block/vold/179:0 /mnt/secure/asec vfat rw,dirsync,nosuid,no
000,gid=1015,fmask=0702,dmask=0702,allow_utime=0020,codepage=cp4
8859-1,shortname=mixed,utf8,errors=remount-ro 0 0
tmpfs /mnt/sdcard/.android_secure tmpfs ro,size=0k,mode=000 0 0
Click to expand...
Click to collapse
error mesg
C:\Users\Mayu>adb push E:\soft\Android\Indic\DroidSansFallback.ttf \system\fonts
failed to copy 'E:\soft\Android\Indic\DroidSansFallback.ttf' to '\system\fonts':
Read-only file system
Click to expand...
Click to collapse
PS: pull works like charm. please guide me if u hav time. Thanks.
DroidMayu said:
Thanks a lot for the tutorial. Basic stuff nicly explained. i tried the push method via adb to push a font into system/fonts directory still it says read only permission
error mesg
PS: pull works like charm. please guide me if u hav time. Thanks.
Click to expand...
Click to collapse
Yup, on an s on system, even though system can be mounted as rewrite, writing isn't allowed. You have to execute the commands in recovery mode
Sent from my HTC Desire using XDA App
Great tutorial! Thanks for that, definitely noob friendly...
Have a question about the following,
DATAOPTS:
(no option) - don't touch the data partition
-w - wipe the data partition
-d - flash the data partition
I have the Samsung Galaxy S I9000 (not sure if that makes a difference) and if my screen breaks or i have some sort of hardware problem. After flashing the stock rom back on do i use the above commands to wipe the evidence of any programs that suggest the device was previously rooted. If so which one wipe or flash?
Thanks
Thank You!!!
Hey Droidzone,
I'm really in awe of you, and need to thank you for the amazing work you're doing here - at XDA.
I just can't find the thank you button on the forums.(I could be blind !!!)
Thanks a zillion!!!

[Emulation] Linux/Ubuntu for android (compatible with cm7/miui)

Hello,
I am going to prensent you today how to install ubuntu on your android device. Some of you propably already tried ,and had problems
making it work (or not). I modified the tutorial to make it easier, and corrected things. I also modified some paths in the scripts so that it can work with
cm7, if you are not a cm7 user you can download the other scripts too.
I based myself on this tutorial:
http://androlinux.com/android-ubuntu-development/how-to-install-ubuntu-on-android/
So let's start !
First, download the following cm7-ubuntu.rar file (decompress and copy over the whole ubuntu directory to the exeternal SD card of your Android smartphone/tablet:
Download cm7-ubuntu.rar:
http://www.fileserve.com/file/KQWsbRG
If you are a miui user, download cm7-ubuntu.rar, and replace the scripts by these:
http://www.fileserve.com/file/Tu8WZP5
If you are a not a cm7 neither a miui user, download cm7-ubuntu.rar, and replace the scripts by these:
http://www.fileserve.com/file/tuVMB9h
1) Make sure your phone is rooted and that busybox installed (if you are on cm7 all is ok).
2) Download Terminal Emulator on the market. Open it and type “su” to enter super user mode, then type “cd /emmc” or "cd /sdcard/external_sd" if your are a miui user or "cd /sdcard" if you are not on cm7, and “cd ubuntu” to enter the ubuntu directory in your SD card of your Android device.
3) Next, type “sh ubuntu.sh” to run the script which will basically get your Ubuntu image ready to run on your Android smartphone/tablet.
If you get error messages, don’t worry and keep going.
4) Type “bootubuntu” to enter Ubuntu. (Next time you enter Ubuntu, you just need to type “bootubuntu” from your /emmc/ubuntu directory, no need to run ubuntu.sh again.
If you got “[email protected]” at this point, congratulations! This means your Android OS comes with loop device support and Ubuntu is now running “chrooted” on top of your Android OS!!!
However, if there is an error like : "losetup: /dev/block/loop2: No such file or directory", this propably means that app2sd is conflicting with your sdcard, so to solve that
move all your applications on your internal sdcard and try again. If this doesn't solve your problem, that means that your kernel doesn't support loop
devices in most of the case, try flashing other kernels.
If after that you still have problems post, and I will try to reply when I have time
5) How to Install Programs on your Ubuntu!
Once you’ve got Ubuntu running on your Android device, it’s time to install some Ubuntu packages(or programs).
Type “apt-get update” to update, this is the first thing you will need to do before installing any new programs.
6) How to Install OpenSSH-server on your Android Ubuntu!
Type “apt-get install openssh-server” to install OpenSSH-server. What is OpenSSH-server? If you want to connect to your Android Ubuntu via an IP address (and SSH into it), you will want to do this.
7) How to Install TightVNCServer on your Android Ubuntu!
If you want to access the GUI of your Android Ubuntu, you can install TightVNCServer, which allows you to access the Android Ubuntu via Android VNC app on your Android smartphone/tablet or even access it remotely from your desktop computer.
Type “apt-get install tightvncserver” to install.
8) How to Install LXDE!(optional)
Next, we will install LXDE (Lightweight X11 Desktop Environment). Although we can use Ubuntu’s default GNOME (and trust me I love that), LXDE takes up less memory so our GUI access will be faster.
If you like GNOME, you can skip this step though.
Type “apt-get install lxde”
How to setup xstartup file so that when TightVNCServer is started, the LXDE runs instead of GNOME:
Type:
export USER = root
vncserver
(here he will ask you for a password for vnc, then if you want a view-only password, this mean you connect to vnc and you cannot interact with ubuntu, say n if you don't want and y if you want)
cat > /root/.vnc/xstartup
#!/bin/sh
xrdb $HOME/.Xresources
xsetroot -solid grey
icewm &
lxsession
Then press Volume-down&D togethe.
9) How fix language and start vnc at each boot:
Type:
touch /root/.bashrc
cat > /root/.bashrc
export LANG=en_US.UTF-8
export USER=root
rm /tmp/.X1-lock
rm /tmp/.X11-unix/X1
vncserver -geometry 1024x800 <== Here, you can change the resolution settings 1024×800 to the resolution of your liking. (Do not write that !)
Then again press Volume-down&D together.
10) Now we are going to reboot ubuntu to apply changes:
Reboot your phone, open Terminal Emulator again and type:
su
bootubuntu
Now your TightVNCServer is ready to accept any incoming connections from your phone or computer. Just point to the correct IP address and use port number 5901 to connect.
On your Android smartphone, just download the free app “Android-VNC-Viewer” and set the IP address to “127.0.0.1″ , port number 5901 and insert the password you set before in password.
Then enjoy !
SHUT DOWN UBUNTU: Sorry you have to reboot the phone, if you try to boot other ubuntu your phone will start to lag
Extra:
If you want more space to install programs & stuff, you can extend your user space without loosing your data.
Requirements:
Linux (you can make a live CD) or just an environment like cygwin for windows
Procedure:
1. UnZip Android or your present ubuntu.img file to your Home Folder. Or a folder of your liking (or even on your memory card!), just remember to cd before you do the following:
2. Open Terminal and Copy&Paste (Ctrl+C, Ctrl+Shift+V) this:
Code:
dd if=/dev/zero bs=1M count=XXX >> ubuntu.img
where XXX is the amount, in MB, by which data.img should be increased by.
My filesize started out as 256MB and I wanted a total of 512MB. That would mean I needed a extra 256MB, so I executed this:
Code:
dd if=/dev/zero bs=1M count=256 >> ubuntu.img
3. Run a file system check and file system resizer
Code:
e2fsck -f ubuntu.img
resize2fs ubuntu.img
e2fsck -f ubuntu.img
if prompted, press "y" for "yes"
4. Copy all of the Android files onto your SD card, put it into your phone...
Source: http://forum.xda-developers.com/showthread.php?t=737826
Sorry for my bad english
If you liked this thread, don't forget there is a Thanks button !
I have a problem with miui chamaleon rc2 . after i type bootubuntu i cant get [email protected] . im thinking that talonmtd dont support loopdevice but i have tried also with plapytus with no luck . you know i kernel with loop support for my rom ?
thanks
Do you have adb ?
MIU is based on cm7, you should have loop support...
do you have the error losetup : /dev/block/loop2: No such file or directory ?
im restarting device and i will copy all the commands . one moment
edit : i get this :
# sh ubuntu.sh
sh ubuntu.sh
modprobe: chdir(/lib/modules): No such file or directory
←[H←[Jmkdir: can't create directory '/data/local/mnt': File exists
←[H←[Jcd: can't cd to /emmc/ubuntu
chmod: bootubuntu: Operation not permitted
chmod: fsrw: Operation not permitted
chmod: mountonly: Operation not permitted
chmod: ubuntu.img: Operation not permitted
chmod: ubuntu.sh: Operation not permitted
chmod: unionfs: Operation not permitted
←[H←[J
Ubuntu Chroot Bootloader v0.1
Ubuntu Bootloader is now installed!
This process does NOT damage Android OS!
Original Installer by Charan Singh
Modified for Ubuntu Chroot by Max Lee at AndroLinux.com ,G2Hacks.com and Ne
eHacks.net
To enter the Ubuntu Linux console just type 'bootubuntu'
# bootubuntu
bootubuntu
mknod: /dev/loop2: File exists
losetup: /dev/block/loop2: No such file or directory
mount: mounting /dev/block/loop2 on /data/local/ubuntu failed: Invalid argu
mount: mounting devpts on /data/local/ubuntu/dev/pts failed: No such file o
ectory
mount: mounting proc on /data/local/ubuntu/proc failed: No such file or dir
y
mount: mounting sysfs on /data/local/ubuntu/sys failed: No such file or dir
y
net.ipv4.ip_forward = 1
Setting /etc/resolv.conf to Google Open DNS 8.8.8.8 and 8.8.4.4
bootubuntu: cannot create /data/local/ubuntu/etc/resolv.conf: directory non
ent
bootubuntu: cannot create /data/local/ubuntu/etc/resolv.conf: directory non
ent
Setting localhost on /etc/hosts
bootubuntu: cannot create /data/local/ubuntu/etc/hosts: directory nonexiste
READY TO ROCK AND ROLL BABY!
Brought to you by NexusOneHacks.net and the open source community!
chroot: can't execute '/bin/bash': No such file or directory
Shutting down Ubuntu
umount: can't umount /data/local/ubuntu/dev/pts: No such file or directory
umount: can't umount /data/local/ubuntu/proc: No such file or directory
umount: can't umount /data/local/ubuntu/sys: No such file or directory
umount: can't umount /data/local/ubuntu: Invalid argument
losetup: /dev/loop2: No such device or address
No, verify you don't have applications on your external sd card, if there is, transfer them to the internal sd card
EDIT: Yes, verify you don't have applications on your sd card
i dont have application on sd card
Okay this is wierd !
2 possibilities :
1. busybox is not installed
2. Your phone do not support loop devices
Can you send me a file in your /proc/ directory named config.gz ? (sorry it is a pain in the ass...)
Oh sorry I forgot how is named your external sdcard ? emmc or sdcard ?
Rename it to *.gz . Xda dont accept gz extension . I looked to sh script and i think the problem is that in cm7 sdcard is /sdcard not /emmc .
my external card is named /sdcard/external_sd and is a 16 gb class 2 so is a bit slower
Okay I think if found, I going to post new scripts for you quickly, I just verify that you have loop support
EDIT: Yes you have loop support, it is scripts
Replace these scripts : http://www.fileserve.com/file/Tu8WZP5
AnonymeLex said:
Okay I think if found, I going to post new scripts for you quickly, I just verify that you have loop support
EDIT: Yes you have loop support, it is scripts
Replace these scripts : http://www.fileserve.com/file/Tu8WZP5
Click to expand...
Click to collapse
Dont worry , but please upload this to xda because i hate fileserve and i have to wait 1200 seconds to download another file . Thanks
Yes, I forgot it's quicker, but does it work finally ?
I think is better that you fix the first post with instruction for miui users
Ok works , thanks a lot
i maked an error .
after this cat > /root/.bashrc i typed :
export LANG=en_US.UTF-8
export USER=root
rm /tmp/.X1-lock
rm /tmp/.X11-unix/X1
vncserver -geometry 800x480
exit
so every time i run bootubuntu this shut down . XD what i have to do to fix that ?
Edit : im recopying all including new script and i will not do same error
I'm using Ubuntu since 2006, it's really nice to see that the interest in Linux is growing so fast!
thunderteaser said:
I'm using Ubuntu since 2006, it's really nice to see that the interest in Linux is growing so fast!
Click to expand...
Click to collapse
im using ubuntu since the first version of android XD . im using it in dual boot . but i have changed 5 pc since 2005 for too use . is in use 24h/7d also with overclock . super pc !!! super android !!
thunderteaser said:
I'm using Ubuntu since 2006, it's really nice to see that the interest in Linux is growing so fast!
Click to expand...
Click to collapse
We can't ignore linux
(
Alberto96 said:
i maked an error .
after this cat > /root/.bashrc i typed :
export LANG=en_US.UTF-8
export USER=root
rm /tmp/.X1-lock
rm /tmp/.X11-unix/X1
vncserver -geometry 800x480
exit
so every time i run bootubuntu this shut down . XD what i have to do to fix that ?
Edit : im recopying all including new script and i will not do same error
Click to expand...
Click to collapse
Oh never thinked we could be in such a situation
The .bashrc is inside ubuntu.img, I don't really see a solution appart redownloading...
Sorry
Wait, exit don't really close ubuntu I think, it juste close terminal you should still able to connect via vnc and modify .bashrc ! To shut it down do Ctrl+D

Easier ADB/Fastboot Usage Mac/Linux

Let's pretend you're running Mac OS X or Linux. You might have your adb and fastboot files in a directory such as:
Code:
~/Android/
Which means to execute the command you have to
Code:
cd ~/Android/
then execute
Code:
./adb
You must be thinking, "There has to be a similar way!" Well, there is!
Code:
sudo cp ~/Android/adb /usr/bin
followed by
Code:
sudo cp ~/Android/fastboot /usr/bin
Now, all you have to do, no matter what you're present location in your file system is to simply type whichever command you want. This will probably speed up using the commands and make your time in terminal a little easier.
It is much more efficient to add the ~Android dir to PATH.
If you ever update your android sdk you'd have to copy the files again.
so better:
Code:
export PATH=~/Android:$PATH
if you want it persistent just change your ~/.profile file (depending on your distribution)
same would work in Windows, there you have to set PATH in the system settings.

The Android Shell

The Android Shell
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.
Currently this documentation is incomplete, sorry!
Common problems
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:
$ dir
dir: permission denied <---- this is a misleading error message, should say 'dir: not found'
$ ls
... listing of current directory
The PATH variable
The Android shell will run any program it finds in its PATH. 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:
$ echo $PATH
/data/local/bin:/sbin:/vendor/bin:/system/sbin:/system/bin:/system/xbin
Depending upon your shell, you may see a different result.
Built in Commands
Every shell has a few built-in commands. Some common built-in commands are:
echo -- prints text to stdout.
set -- sets shell variables
export -- makes shell variables available to command-line programs
cd -- change the current directory.
pwd -- print name of the current directory.
Commands
To find out what commands you have available to you, use the "ls" command on each of the directories in the PATH variable.
Finding documentation for the Android commands.
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".
List of commands
The following is a list of the commands that are present on a Nexus S phone running an Android 2.3.3 "user-debug" build. 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.)
$ ls /data/local/bin
/data/local/bin: No such file or directory
Notice that by default there is no /data/local/bin directory. You can create this directory using the "mkdir" command if you like.
$ ls /sbin
opendir failed, Permission denied
The /sbin directory exists, but you don't have permission to access it. 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.
$ su
# ls /sbin
ueventd
adbd
# exit
$
Notice that the shell prompt changes from a '$' to a '#' to indicate that you have root access.
Notice also that neither of the /sbin commands are useful to the shell -- the adb and ueventd files are 'daemon' programs used to implement the Android Debugger "adb" program that is used by developers.
$ ls /vendor/bin
gpsd
pvrsrvinit
Vendor/bin is where device vendors can put device-specific executables. These files are from a Nexus S.
$ ls /system/sbin
/system/sbin: No such file or directory
This directory does not exist on a Nexus S.
$ ls /system/bin
am
am is the Android Activity Manager. It's used to start and stop Android activities (e.g. applications) from the command line. Type am by itself to get a list of options.
amix
aplay
Command line audio file player.
app_process
applypatch
Used to apply patches to android files.
arec
Command line audio recorder.
audioloop
bluetoothd
BlueTooth daemon
bmgr
Backup manager - type command by itself to get documentation.
bootanimation
Draws the boot animation. You may have to reset your phone to get out of this.
brcm_patchram_plus
bugreport
cat
Copy the contents of a file to standard output.
chmod
Change the mode of a file (e.g. whether it can be read or written.)
chown
Change the owner of a file.
cmp
Compare two files byte-by-byte
dalvikvm
The dalvik virtual machine. (Used to run Android applications.)
date
Prints the current date and time
dbus-daemon
dd
Convert and copy a file. By default copies standard in to standard out.
debuggerd
dexopt
df
Shows how much space is free on different file systems on your device.
dhcpcd
dmesg
dnsmasq
dumpstate
dumpsys
dvz
fsck_msdos
gdbserver
getevent
getprop
gzip
hciattach
hd
id
ifconfig
Shows the current configuration of network interfaces (IP, MAC address etc)
iftop
Shows the current processes using the network interfaces (top, but for networks)
ime
input
insmod
installd
ioctl
ionice
iptables
Manage the firewall
keystore
keystore_cli
kill
Send signals to processes.
linker
ln
Used to set up a file system link.
log
logcat
Prints the Android runtime log.
logwrapper
ls
Lists files.
lsmod
lsof
make_ext4fs
mediaserver
mkdir
Make a directory.
monkey
A program that sends random events, used to test applications. (Like having a monkey playing with the device.)
mount
mtpd
mv
Move a file from one directory to another. (Only on the same file system. Use "cat a > b" to copy a file between file systems.
nandread
ndc
netcfg
netd
netstat
newfs_msdos
notify
omx_tests
pand
ping
pm
pppd
printenv
ps
List active processes.
qemu-props
qemud
racoon
radiooptions
reboot
Reboot the device.
record
renice
rild
rm
Remove a file.
rmdir
Remove a directory.
rmmod
route
rtp_test
run-as
schedtest
schedtop
sdcard
sdptool
sendevent
service
servicemanager
setconsole
setprop
setup_fs
sh
showlease
sleep
smd
stagefright
start
Starts the Android runtime.
stop
Stops the Android runtime.
surfaceflinger
svc
sync
system_server
tc
testid3
toolbox
top
Shows which processes are currently using the most CPU time.
umount
uptime
Prints how long your device has been running since it was last booted.
vdc
vmstat
vold
watchprops
wipe
wpa_cli
wpa_supplicant
$ ls /system/xbin
add-property-tag
btool
check-lost+found
dexdump
dhdutil
hcidump
latencytop
librank
opcontrol
oprofiled
procmem
procrank
rawbu
scp
Secure copy program. (Used to copy files over the network.)
showmap
showslab
sqlite3
Used to administer SQLite databases.
strace
System trace command - use to see what system calls a program makes.
su
Start a shell with root privileges.
Versions of the Android Shell
Android 1.0 used a shell that had no tab completion or history editing.
Android 2.3 added history editing. You can for example use the up/down arrows to edit previous commands.

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