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index

Modify the authority of folder(s) or file(s)

1) To modify the ownership of file(s).

$ chown -R USER.NAME OBJ.NAME

2) To modify the group ownership of file(s).

$ chgrp -R GROUP.NAME OBJ.NAME
OR directly like this to change ownership and group at a time:

$ chown -R USER.NAME:GROUP.NAME OBJ.NAME

TAR

1) Extract.

tar xvfj TARBALL.tar.bz2
tar xvfz TARBALL.tar.gz

2) Compress.

tar cvfj TARBALL.tar.bz2 FOLDERtoCOMPRESS
tar cvfz TARBALL.tar.gz FOLDERtoCOMPRESS

Mount Compile Server

Problem description

$ sudo mount -t nfs -o nolock 192.168.1.71:/home/yliao /home/yliao/mnt/compile_server
mount.nfs: access denied by server while mounting 192.168.1.71:/home/yliao

Solution

$ sudo /etc/init.d/nfs-kernel-server start

(NOTE: Run this command on server.)

Run scripts automatically

Just modify this file "/etc/rc.d/rc.local", cause this script will run on each boot up.

Run command in another process without suspend terminal

Add a & just follow the command sequence, such as:
$ gedit xxx.c &
Then there will print a PID repesent that process. When it is finished, there will print some message, too.

find and delete

Delete specific files(dirs). As,
find . -name ".svn" -exec rm -rf {} \;

find only dir or file to do something

chmod only for directories:
find . -type d -exec chmod 755 {} \;
chmod only for files:
find . -type f -exec chmod 644 {} \;

find text and replace

sed -i 's/TO_BE_REPLACED/NEW_STRING/g' FILE_NAME1 FILE_NAME2 ...
and we can also use following line to delete the last line:
sed -i '$d' FILE_NAME
delete the line matches string "chromium":
sed -i '/chromium/d' FILE_NAME

remove trailing white spaces

sed -i 's/[ \t]*$//g' FILE_NAME1 FILE_NAME2 ...

install openssh-server for remote accessing by others

sudo apt-get install openssh-server

scp simple usage

scp yliao@192.168.1.71:/home/yliao/work/marlin4xxu.tar.bz2 .

Concatenate files and output to a new file

cat file1 file2 > newfile

Bluetooth Driver in Fedora 15

The three main command we may use: hciattach, hciconfig, hcitool
$ lsusb
Bus 006 Device 003: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)
$ sudo hciconfig hci0 down
$ sudo hciconfig hci0 up
$ hcitool scan
If succeed, it would be like this:
Scanning ...
00:10:11:07:00:05 HC-05
Then we can use hci to control the Bluetooth Adapter.

tftp server

(on UBUNTU 11.04 32-bit)
1) sudo apt-get install xinetd tftp tftpd-hpa
2) Create a new file /etc/default/tftpd-hpa:

#/etc/default/tftpd-hpa

TFTP_USERNAME="tftp"
TFTP_DIRECTORY="/opt/tftpboot"
TFTP_ADDRESS="192.168.1.130:69"
TFTP_OPTIONS="--secure"

3) sudo service tftpd-hpa start
tftpd-hpa start/running, process 17318 That is ok.
4) Testing
tftp 192.168.1.130

tftp> get image_yliao/sm/uImage

Sourcery Tools Support Portal (Also resolve the problem to run 32-bit excutables on a 64-bit)

On Android building, I got: bash: arm-eabi-gcc: no such file or directory
After I resolve the CodeSourcery 64-bit problem, the GTV building can continue.
Maybe just need some packages to install.
Source: https://sourcery.mentor.com/GNUToolchain/kbentry62

What do I need to do to install and run Sourcery CodeBench on an x86 64-bit Linux host system?
In order to use Sourcery CodeBench on an x86 64-bit Linux host system, you must have 32-bit system libraries installed. You can install these 32-bit libraries using your system's package management tool, or build them from source.
Distribution Notes:

Debian/Ubuntu
The following 32-bit libraries are available as packages that can be installed using apt-get on the command line or graphically using Synaptic:

ia32-libs
ia32-libs-gtk (not required for Hardy 8.04 and later)

To install these packages from the command line:
sudo apt-get install ia32-libs ia32-libs-gtk
Next you will need to use Getlibs to install a 32-bit version of xulrunner:

Download getlibs-all.deb
Install getlibs-all.deb by running:
sudo dpkg -i getlibs-all.deb
Install the 32-bit xulrunner by running:
sudo getlibs -p xulrunner-1.9.2 (not necessary)
Setup the IDE to use your recently installed 32-bit xulrunner:
export MOZILLA_FIVE_HOME=/usr/lib32/xulrunner-1.9.2.X (not necessary)
Substitute X for the version you see installed on your system. You will need to set this environment variable every time you start the IDE.

Red Hat Enterprise Linux
The following 32-bit library is available as a package that can be installed using the up2date command:

glibc-devel

To install this package from the command line:
up2date-nox -i --arch=i386 glibc

Fedora
If working with a new installation of the operating system please run yum update before attempting the following steps.
Logged in as the root user run the following:

Fedora 14:
yum install glibc-devel.i686 gtk2-devel.i686 gtk-nodoka-engine.i686 \
libcanberra.i686 libcanberra-gtk2.i686 PackageKit-gtk-module.i686 \
GConf2.i686 ncurses-libs.i686 xulrunner.i686
Fedora 11:
yum install glibc-devel.i586 gtk2-devel.i586 gtk-nodoka-engine.i586 \
libcanberra.i586 libcanberra-gtk2.i586 PackageKit-gtk-module.i586 \
GConf2.i586 ncurses-libs.i586 xulrunner.i586

Generic Linux
The following 32-bit libraries must be installed with versions greater than or equal to those listed here:

GLIBC 2.3
GTK 2.2.1
ATK 1.2.0
glib 2.2.1
Pango 1.2.1
Freetype 2.1.3
Ncurses 5.0
XULRunner 1.9.1

Install Sun Java in Ubuntu 11.04

Since sun java is not in ubuntu official repo source, we need to add it:
sudo add-apt-repository ppa:ferramroberto/java
sudo apt-get update
sudo apt-get install sun-java6-jre sun-java6-plugin sun-java6-jdk

Download Directories from FTP use wget

Such as:
wget ftp://ftp.cn.freebsd.org/pub/FreeBSD/releases/amd64/8.2-RELEASE/* -r

Components Needed for Fedora 15

gnome-tweak-tool
dconf-editor

Fedora Group Install Development Tools

sudo yum groupinstall 'Development Tools'

Call a Command, a Program or a Script, then Print the Log to a File

COMMAND >& FILENAME
e.g.
ls / >& log
Or even the command does not exist, the result "command not found" will also be there:
lk / >& log

shortcuts in LXDE

For now, I just find the only way to modify shortcut keys.
modify this file: /home/USERNAME/.config/openbox/lxde_rc.xml or something alike.

Fedora 16 NFS Server

First of all,
sudo yum install nfs-utils
Then, run
system-config-firewall
In this application, open ports related to nfs: 111, 2049
Next, edit etc/exports to add the directory you would like to use as nfs, like:
/home/librae/workspace/tq *(rw,sync,no_root_squash)
Operation above can be checked with sudo exportfs -v
After that, go to edit nfs configuration files,
sudo mv /etc/sysconfig/nfs /etc/sysconfig/nfs.bak
sudo mv /etc/sysconfig/nfs.rpmnew /etc/sysconfig/nfs
Then edit /etc/sysconfig/nfs to include whatever you actually need from /etc/sysconfig/nfs.bak
My /etc/sysconfig/nfs file:

#
# Path to remote quota server. See rquotad(8)
#RQUOTAD="/usr/sbin/rpc.rquotad"
# Port rquotad should listen on.
RQUOTAD_PORT=875
# Optinal options passed to rquotad
RPCRQUOTADOPTS=""
#
# Optional arguments passed to in-kernel lockd
#LOCKDARG=
# TCP port rpc.lockd should listen on.
LOCKD_TCPPORT=32803
# UDP port rpc.lockd should listen on.
LOCKD_UDPPORT=32769
#
# Optional arguments passed to rpc.nfsd. See rpc.nfsd(8)
RPCNFSDARGS=""
# Number of nfs server processes to be started.
# The default is 8.
RPCNFSDCOUNT=8
# Set V4 grace period in seconds
#NFSD_V4_GRACE=90
#
# Optional arguments passed to rpc.mountd. See rpc.mountd(8)
RPCMOUNTDOPTS=""
#
# Optional arguments passed to rpc.statd. See rpc.statd(8)
STATDARG=""
#
# Optional arguments passed to rpc.idmapd. See rpc.idmapd(8)
RPCIDMAPDARGS=""
#
# Optional arguments passed to rpc.gssd. See rpc.gssd(8)
RPCGSSDARGS=""
#
# Optional arguments passed to rpc.svcgssd. See rpc.svcgssd(8)
RPCSVCGSSDARGS=""
#
# To enable RDMA support on the server by setting this to
# the port the server should listen on
#RDMA_PORT=20049
#
# Optional arguments passed to blkmapd. See blkmapd(8)
BLKMAPDARGS=""

Well, config ok now, let's enable and start nfs-server service
sudo systemctl enable nfs-server.service
sudo systemctl start nfs-server.service
All done. Reboot computer and use this to verify:
sudo systemctl status nfs-server.service
rpcinfo -p
NOTE!
We MUST ensure these services are running:

systemctl status rpcbind.service
systemctl status nfs-server.service
systemctl status nfs-lock.service
systemctl status nfs-idmap.service

On client machines, we use following command to mount this nfs server, like:
sudo mount -t nfs 192.168.11.6:/home/librae /home/librae/mnt/nbook

Tips:
check nfs service: systemctl -a | grep nfs
nfs config files are located in /etc/sysconfig
external links:
http://www.server-world.info/en/note?os=Fedora_16&p=nfs
 http://weisjohn.blog.163.com/blog/#m=0&t=3&c=nfs
 http://forums.fedoraforum.org/showthread.php?t=273173

Actually, this version of nfs can be started easily, steps above are redundent.

  1. edit /etc/exports
  2. start those four services
  3. All done!

Check pts no. & Communication Between Terminals

ls -hl /proc/self/fd
This will print the pts no. you are on.
e.g.:

yliao@yliao-l-d:~/Public/librae8226.github.com$ ls /proc/self/fd -hl
total 0
lrwx------ 1 yliao yliao 64 2011-12-19 15:08 0 -> /dev/pts/10
lrwx------ 1 yliao yliao 64 2011-12-19 15:08 1 -> /dev/pts/10
lrwx------ 1 yliao yliao 64 2011-12-19 15:08 2 -> /dev/pts/10
lr-x------ 1 yliao yliao 64 2011-12-19 15:08 3 -> /proc/1610/fd

Then if we type
echo "Hi there" > /dev/pts/10
See what will happen :P

Build RaLink RT3090 WLAN Card Driver Manually (FC16)

Foreword
--------
Machine: Lenovo B450 (RT3090 Wireless 802.11n 1T/1R PCIe) (use lspci -vnn to see it)
OS: Fedora 16
Results: Failed to connect my notebook to wifi ap router, but use this driver, we can scan the environment, indeed. That is, it works.

Procedure
---------

  1. Download rpm src from RussianFedora: http://koji.russianfedora.ru/koji/buildinfo?buildID=750
  2. Extract it and we can see a folder like rt3090-kmod-2.4.0.4-3.fc16.8.R.src
  3. Patch all the patches in the folder to src files in 2010_1217_RT3090_LinuxSTA_V2.4.0.4_WiFiBTCombo_DPO.zip
    use patch -p0 xxx.patch in the .src root folder is just fine.
  4. make
  5. sudo make install
  6. blacklist rt2800, rt28xx drivers in /etc/modprobe.d/blacklist.conf
  7. depmod -a ${shell uname -r}
  8. reboot
  9. bringup: sudo ifconfig ra0 up
  10. scan: iwlist ra0 scan
  11. connect: sudo iwconfig ra0 essid XXXX
  12. longging to further debugging....

Fedora 16 Fail to Bootup into Graphics Because of NVIDIA Driver

Do below steps to remove nvidia driver and enable default noveau driver,
then install nvidia driver again.

su
yum remove nvidia*
mv /boot/initramfs-$(uname -r)-nouveau.img /boot/initramfs-$(uname -r).img
dracut /boot/initramfs-$(uname -r).img $(uname -r)
removed "rdblacklist=nouveau nouveau.modeset=0" from GRUB_CMDLINE_LINUX
grub2-mkconfig -o /boot/grub2/grub.cfg
reboot

Fedora 16 Get USB access priority

sudo usermod -a -G uucp,dialout,lock $USER
Then logout -> login

Fedora 16 Chrome Shockwave Flash Player Crash

Add line below in Chrome script /opt/google/chrome/google-chrome
export LD_PRELOAD=/usr/lib/libGL.so.1

Fedora 16 Disable SELinux

Temporary:
sudo setenforce 0
Always:
vi /etc/sysconfig/selinux
Then set it to disabled

Fedora 16 Setup TFTP Server

sudo yum install tftp*
vi /etc/xinetd.d/tftp
--------------------------------------------
service tftp
{
	disable		= no
	socket_type	= dgram
	protocol	= udp
	wait		= yes
	user		= root
	server		= /usr/sbin/in.tftpd
	server_args	= -s /opt/tftpboot
	per_source	= 11
	cps		= 100 2
	flags		= IPv4
}
--------------------------------------------
sudo /sbin/chkconfig tftp on
sudo systemctl enable xinetd.service
sudo systemctl start xinetd.service

vi /etc/sysconfig/iptables
----------------------------------------------------------------
-A INPUT -m state --state NEW -m udp -p udp --dport 69 -j ACCEPT
----------------------------------------------------------------

vi /etc/sysconfig/selinux
----------------
SELINUX=disabled
----------------

Fedora 16 Samba Service

sudo yum install samba samba-client
sudo systemctl enable smb.service
sudo systemctl start smb.service

Use below command to mount target samba server:
sudo mount.cifs //10.38.120.39/tftpboot /home/yrliao/mnt/tftp_mv -o username=yrliao,password=123456

Make ssh/scp/rsync work Without Password

Make use of a file ~/.ssh/authorized_keys (mode 700) is just fine.
Refer to externel link:
https://blogs.oracle.com/jkini/entry/how_to_scp_scp_and

Fedora 16 LXDE Keyboard Layout Problem

use command below to set it to default, us layout:
setxkbmap us

Fedora 16 LXDE Desktop Icons Disappear

lxde --desktop &

Fedora 16 LXDE Desktop Openbox Reload "lxde-rc.xml"

openbox --reconfigure
Refer to this link:
http://linux-commands.wikidot.com/howto-s:lxde

Fedora 16 Make It Work: Bluetooth Dongle with HC-05 rfcomm

1. Install "blueman".
# yum install blueman
2. Connect Bluetooth dongle and slave HC-05.
3. Search and pair device.
4. Right click HC-05 in blueman, select "Dev B".
Serial port connected to /dev/rfcomm0
5. minicom -s (rfcomm0)

Restore Files That Was Removed by rm -rf

1. Download extundelete from http://extundelete.sourceforge.net/
2. It needs e2fslib, so install them:
# yum install e2fslib* for Fedora.
# apt-get install e2fslib* for Ubuntu.
3. Put/excute extundelete in /tmp to avoid unexpected loss.
4. Make sure the filesystem to be restored is unmount. So if it's home, we may use a dual boot OS to do this.
5. Run:

# extundelete --restore-files [OFFSET_PATH_OF_FS] [FS]
/*
 * Such as:
 * # extundelete --restore-files yrliao/workspace/sandlib/cpu_stat/stat.c /dev/sda6
 */

Check What Files Are Opened by A Particular Process

	ls -l /proc/7857/fd

List the First 10 Processes that Consume Most Memory

ps -e -o 'pid,comm,args,rsz,vsz,user' | sort -nrk4 | head

Check Net Ports Status

Quotes from man nmap:
The SYN scan and SYN ping (-sS and -PS) are very detailed,
but the TCP connect scan (-sT) is limited by the implementation of the connect system call.

# nmap -sT -O localhost
OR
# nmap -sS -O localhost

And we can also use this:

$ netstat -lntu

Create A swapfile for Linux

# install -o root -g root -m 0600 /dev/null /swapfile
# dd if=/dev/zero of=/swapfile bs=1k count=1024k
# mkswap /swapfile
# swapon /swapfile
# echo "/swapfile       swap    swap    auto      0       0" | tee -a /etc/fstab
# sysctl -w vm.swappiness=10
# echo vm.swappiness = 10 | tee -a /etc/sysctl.conf

Referred to: https://meta.discourse.org/t/create-a-swapfile-for-your-linux-server/13880

Find Regular Files Only (Ignore Directories)

e.g in Makefile:

@find $(SRCDIR) -name \*.o -prune -type f | xargs $(RM)
@find $(SRCDIR) -name \*.d -prune -type f | xargs $(RM)

Sort for Particular Columns

e.g. in ousia build - sizes file:

cat build/ousia.sizes | sort -k1,1n
      0	      0	      0	      0	      0	build/core/sys_ds.o
      0	      0	      0	      0	      0	build/core/sys_ictl.o
      0	      0	      0	      0	      0	build/framework/vfs/fileops.o
      0	      0	      0	      0	      0	build/platform/stm32/libmaple/stm32f1/fsmc.o
      0	      0	      0	      0	      0	build/platform/stm32/libmaple/stm32f1/performance/vector_table.o
   text	   data	    bss	    dec	    hex	filename
      2	      0	      0	      2	      2	build/platform/stm32/libmaple/stm32f1/performance/isrs.o
     20	      0	      0	     20	     14	build/platform/stm32/libmaple/flash.o
     20	      0	      0	     20	     14	build/platform/stm32/libmaple/gpio.o
     20	      0	      0	     20	     14	build/platform/stm32/libmaple/pwr.o
     24	      0	      0	     24	     18	build/core/sys_main.o
     24	      0	      0	     24	     18	build/platform/stm32/libmaple/start.o
     28	      0	      0	     28	     1c	build/platform/stm32/libmaple/stm32f1/exti.o
     36	      0	      0	     36	     24	build/platform/stm32/libmaple/usart_private.o
     48	      0	      4	     52	     34	build/core/sys_sync.o
     52	      0	      0	     52	     34	build/platform/stm32/libmaple/iwdg.o
     56	      0	      0	     56	     38	build/platform/stm32/libmaple/usb/usb_lib/usb_init.o
     64	      0	      4	     68	     44	build/core/sys_time.o
     92	      0	      0	     92	     5c	build/platform/stm32/libmaple/usb/usb_lib/usb_mem.o
     96	      0	      0	     96	     60	build/platform/stm32/libmaple/exc.o
    104	      0	      0	    104	     68	build/core/sys_debug.o
    104	      0	      0	    104	     68	build/platform/stm32/libmaple/dma.o
    112	      0	      0	    112	     70	build/platform/stm32/libmaple/start_c.o
    116	      0	      0	    116	     74	build/platform/stm32/libmaple/adc.o
    120	      0	      4	    124	     7c	build/project/sample_stm32/main.o
    128	      0	      0	    128	     80	build/platform/stm32/libmaple/util_hooks.o
    132	     24	      0	    156	     9c	build/platform/stm32/libmaple/stm32f1/spi.o
    140	     24	      0	    164	     a4	build/platform/stm32/libmaple/stm32f1/adc.o
    144	      0	      0	    144	     90	build/platform/stm32/libmaple/nvic.o
    152	      0	      0	    152	     98	build/platform/stm32/libmaple/rcc.o
    188	      8	      0	    196	     c4	build/platform/stm32/libmaple/stm32f1/bkp.o
    200	      0	      0	    200	     c8	build/platform/stm32/libmaple/dac.o
    200	      0	      8	    208	     d0	build/platform/stm32/libmaple/systick.o
    212	     32	      0	    244	     f4	build/platform/stm32/libmaple/stm32f1/gpio.o
    240	      0	      0	    240	     f0	build/platform/stm32/libmaple/spi.o
    256	      0	      0	    256	    100	build/platform/stm32/libmaple/usb/stm32f1/usb_reg_map.o
    288	    112	      0	    400	    190	build/platform/stm32/libmaple/stm32f1/i2c.o
    344	      0	      4	    348	    15c	build/core/ulib/string.o
    360	      0	      0	    360	    168	build/core/sys_mm.o
    368	      0	      0	    368	    170	build/platform/stm32/libmaple/usart.o
    428	      0	      8	    436	    1b4	build/platform/stm32/libmaple/util.o
    484	    252	     36	    772	    304	build/platform/stm32/libmaple/stm32f1/usart.o
    520	      0	      0	    520	    208	build/core/ulib/stdlib.o
    520	     20	      0	    540	    21c	build/platform/stm32/libmaple/stm32f1/rcc.o
    556	      0	      0	    556	    22c	build/platform/stm32/libmaple/stm32f1/timer.o
    572	      0	     64	    636	    27c	build/project/sample_stm32/eeprom.o
    688	      0	    128	    816	    330	build/platform/stm32/libmaple/exti.o
    784	      0	     16	    800	    320	build/core/sys_print.o
    868	      0	      0	    868	    364	build/framework/console/cmd.o
    908	     20	      0	    928	    3a0	build/platform/stm32/libmaple/usb/stm32f1/usb.o
    928	    164	      0	   1092	    444	build/platform/stm32/libmaple/timer.o
   1060	      0	    464	   1524	    5f4	build/framework/console/console.o
   1188	      0	     36	   1224	    4c8	build/core/sys_utils.o
   1276	      4	      1	   1281	    501	build/platform/stm32/utils/utils.o
   1304	     68	      0	   1372	    55c	build/platform/stm32/libmaple/stm32f1/dma.o
   1460	      0	      0	   1460	    5b4	build/core/mm_std.o
   1600	    192	     86	   1878	    756	build/platform/stm32/libmaple/usb/stm32f1/usb_cdcacm.o
   1776	      0	      0	   1776	    6f0	build/platform/stm32/libmaple/i2c.o
   1852	      0	     16	   1868	    74c	build/platform/stm32/port/ousia_port.o
   1968	      0	      0	   1968	    7b0	build/platform/stm32/libmaple/usb/usb_lib/usb_regs.o
   2344	      0	      1	   2345	    929	build/platform/stm32/libmaple/usb/usb_lib/usb_core.o
   2544	      0	   2048	   4592	   11f0	build/project/sample_stm32/mlcd.o
   2556	      0	     36	   2592	    a20	build/core/sys_sched.o
  32674	    920	   2964	  36558	   8ece	(TOTALS)

Delete Specific Line(s) in Some File(s)

Those lines contains "sm_api.h" will be deleted.

sed -i '/sm_api\.h/d' `find . -name \*.c`

Reading from a continuously changing logfile

In below case, btsnoop_hci.log.txt is growing:

tail -f /sdcard/btsnoop_hci.log.txt