Linux: Difference between revisions

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Line 371: Line 371:
netmask 255.255.255.0
netmask 255.255.255.0
network 192.168.1.0
network 192.168.1.0
broadcast 192.168.1
broadcast 192.168.1.255
.255
dns-nameservers 192.168.1.1 8.8.8.8
</pre>
</pre>
After it, restart network
After it, restart network
Line 378: Line 378:
/etc/init.d/networking restart
/etc/init.d/networking restart
</pre>
</pre>
OR
sudo reboot
Note: It does not work by editing /etc/resolv.conf since this file will be overwritten.


=== Change IP address from the command line ===
=== Change IP address from the command line ===

Revision as of 22:00, 20 January 2013

Handy Linux tips

colordiff-color in terminal diff

Need to install first. apt-get install colordiff. http://www.cyberciti.biz/programming/color-terminal-highlighter-for-diff-files/

Listen to pandora in Europe: install squid proxy

http://www.cyberciti.biz/faq/access-pandora-radio-using-proxy-server-outside-usa/

Interestingly, the firefox connection settings should choose HTTP Proxy instead of 'SOCKS host'.

Bypass blocked website from work computer

http://www.panix.com/~ruari/censorship.html 

ssh -D 4096 user@remoteip
ssh -D 4096 -p 23 user@remoteip

This will require you to enter the password and leave you in the remote machine. If a nonstandard port is required, we can use -p option.

Now in the firefox, we need to go to Edit -> Preferences -> Advanced -> Network tab -> Settings... Check 'Manual proxy configuration' (The default is 'Use system proxy settings') and enter 'localhost' for SOCKS Host and '4096' for the Port. Don't enter 'localhost' in the HTTP Proxy.

On Windows, we can use Putty. In short, in the left-hand panel, navigate through Connection > SSH > Tunnels. Enter 4096 in the Source Port box and select the Dynamic radio button. Click Add and “D4096″ will appear in the Forwarded Ports list. The setting in the firefox end is the same.

Graphical way to display disk usage

For example, to use xdiskusage, we run apt-get install xdiskusage and launch it by xdiskusage ~/.

Display directory size with sorting and human readable

du -k ~/ --max-depth=1 --exclude ".*" | sort -nr | cut -f2 | xargs -d '\n' du -sh

The --exclude is to hide hidden directories.

Note that the 'du' commands may be cheating. See the following screenshot.

DiskUsage.png

The discrepancy is explained by 'sector'. See http://askubuntu.com/questions/122091/difference-between-filesize-and-size-on-disk. 

$ sudo dumpe2fs /dev/sda1 | grep -i "block size"
dumpe2fs 1.41.14 (22-Dec-2010)
Block size:               4096

To show a file size in terms of blocks, we can use 

ls -s

So for example, if a file takes 150 blocks, and if a block takes 4096 bytes, then the file takes 150*4096/1024 KB on disk.

Apache benchmark (ab) testing

ab -n 100 -c 10 http://taichi.selfip.net:81/
ab -n 100 -c 10 http://taichi.selfip.org/

rsync with non-standard port

Use -e option 

rsync -avz -e "ssh -p 23" mydir user@remoteip:

rsync with progress bar

Use --progress option. 

rsync -avz --progress file1 file2

The 'rsync' command works on transferring files local to local too.

scp with non-standard port

Use -P argument. 

ssh -P 23 myfile user@remoteip:

The device is busy

See http://ocaoimh.ie/2008/02/13/how-to-umount-when-the-device-is-busy/ 

# fuser -m /dev/sdc1
/dev/sdc1: 538
# ps auxw|grep 538
donncha 538 0.4 2.7 219212 56792 ? SLl Feb11 11:25 rhythmbox

Another handy one is: 

umount -l /dev/sdwhatever

Kill a process

kill -9 PID

Create an ext3 file system on a USB flash drive

umount /dev/sdb1   (depending on the device of course)
sudo mkfs.ext3 /dev/sdb1
sudo e2label /dev/sdb1 usbdrive   (change the label)

We can create MS-DOS file system by 

sudo mkfs.vfat /dev/sdb1

Port forwarding

For example, we like to use source port number 8080, destination port 80 (the http port), and destination server www.ubuntuforums.org. 

ssh -L 8080:www.ubuntuforums.org:80 <host>

Where <host> should be replaced by the name of your laptop. The -L option specifies local port forwarding. For the duration of the SSH session, pointing your browser at http://localhost:8080/ would send you to http://www.ubuntuforums.org/.

To stop the ssh session, use ps -ef to find the process id and kill it.

Add a new user with home directory

adduser xxx

adduser is better than useradd since useradd does not create home directory and it does not even ask the password for new user. adduser will interactively ask user information.

To delete the user, use 

deluser xxx

Compress a folder without full path name

Suppose we want to compress the folder ~/Documents and its subfolders. We want to include Documents folder name but not /home/brb/Documents name. 

tar -czvf tmp.tar.gz -C ~/ Documents
tar -tzvf tmp.tar.gz

Show folder size for one level only

du --max-depth=1 -h

Soft link

ln -s /full/path/of/original/file /full/path/of/soft/link/file

Backup

  • Use dropbox folder.

If we don't want to install dropbox software, we can install bash dropbox uploader: http://www.andreafabrizi.it/?dropbox_uploader

I install it under ~/Downloads/andreafabrizi-Dropbox-Uploader-cdc2466 directory

Sample usages: 

./dropbox_uploader.sh  list /
./dropbox_uploader.sh  upload ~/Desktop/ConfigurateNote.txt

Running a cron job as a user

  • crontab cron-file-winter; crontab -l

Make sure the .sh file gives a complete path. For example, 

#!/bin/sh
R --vanilla  < arraytoolsip.R

does not work in cron job although it works perfect when we manually run it from the right path. The sh file should be 

#!/bin/sh
R --vanilla  < $HOME/Dropbox/scripts/arraytoolsip.R

Running crontab as root

Use sudo crontab -e to edit. After saving it, no need to initialize it. Use sudo crontab -l to list the cron job.

Mount usb drive

Run 

fdisk -l

OR 

dmesg | grep -i "SCSI"

to confirm the USB device is detected.

Now suppose the usb device is found in dev/sdb1. 

mkdir /mnt/usb
mount -t vfat -o rw,users /dev/sdb1 /mnt/usb

The above mount command assumes the usb drive has Windows vfat partition and users give non-root users the ability to unmount the drive. If the USB drive is partitioned linux ext2/3, we can merely run mount command as 

mount /dev/sdb1 /mnt/usb

At the end, run umount command like 

umount /mnt/usb

To make the mounting automatically, edit the file /etc/fstab. 

/dev/sdb1       /mnt/usb           vfat    defaults        0       0 
/dev/sdb1       /mnt/usb           ext3    defaults        0       0

and run 

mount -a


run commands in a background and allow log off

nohup /path/to/script >output 2>&1 &

vi keys

  • editmode / insert: "i"
  • editmode / append: "a"
  • leave edit mode: "ESC"
  • save: ":w"
  • quit: ":q"
  • save and quit: ":wq"
  • quit without saving: ":q!"

Some helps

Cloud

http://slidedecks.wilmoore.com/2012-confoo/diy-private-cloud-using-virtualBox-and-chef/#66

http://www.datacentermap.com/blog/cloud-software-389.html

U-boot

http://www.denx.de/wiki/U-Boot

Pandora linux client

http://kevinmehall.net/p/pithos/

COW (copy on write) file system

The cow filesystem was found on xubuntu live CD. See http://en.wikipedia.org/wiki/Copy-on-write

Apache redirection

http://cran.r-project.org/mirror-howto.html

Important linux directories

  • /bin - executables used by the base system
  • /boot
  • /dev
  • /etc - configuration files
  • /media
  • /mnt
  • /opt - optional application packages
  • /proc - process information only
  • /sbin - critical executables for running the system, but should be used by superuser
  • /usr - non-critical files. Inside is /usr/bin, which contains most of the libraries used by apps.
  • /var - variable data such as databases, mails spools and system logs.

List of available (uninstalled) packages

aptitude -F "%p" search "?not(?installed)"

See http://superuser.com/questions/408082/how-do-i-get-a-list-of-available-i-e-uninstalled-packages-in-debian

List of installed packages

dpkg --get-selections

Debian/Ubuntu/Bio-Linux

BioLinux

Bio-Linux 7.0 (2012/11/21) screenshot.

BioLinux.png

Apache configuration

https://help.ubuntu.com/11.10/serverguide/httpd.html

Device manager

By default, ubuntu does not provide any graphical tool like device manager on Windows. A very close one is lshw (hardware lister). A GUI tool based on it is called lshw-gtk and can be installed by sudo apt-get install lshw-gtk in Ubuntu/Debian or yum install lshw in Red Hat/Fedora/CentOS. 

$ sudo lshw -short
H/W path        Device      Class       Description
===================================================
                            system      To Be Filled By O.E.M. (To Be Filled By O.E.M.)
/0                          bus         970 Extreme4
/0/4                        processor   AMD Sempron(tm) 145 Processor
/0/4/5                      memory      128KiB L1 cache
/0/4/6                      memory      1MiB L2 cache
/0/10                       memory      8GiB System Memory
/0/10/0                     memory      2GiB DIMM DDR3 Synchronous 667 MHz (1.5 ns)
/0/10/1                     memory      2GiB DIMM DDR3 Synchronous 667 MHz (1.5 ns)
/0/10/2                     memory      2GiB DIMM DDR3 Synchronous 667 MHz (1.5 ns)
/0/10/3                     memory      2GiB DIMM DDR3 Synchronous 667 MHz (1.5 ns)
/0/0                        memory      64KiB BIOS
/0/100                      bridge      RD890 PCI to PCI bridge (external gfx0 port B)
/0/100/2                    bridge      RD890 PCI to PCI bridge (PCI express gpp port B)
/0/100/2/0                  display     RV770 [Radeon HD 4850]
/0/100/2/0.1                multimedia  RV770 HDMI Audio [Radeon HD 4850/4870]
/0/100/9                    bridge      RD890 PCI to PCI bridge (PCI express gpp port H)
/0/100/9/0                  bus         ASM1042 SuperSpeed USB Host Controller
/0/100/a                    bridge      RD890 PCI to PCI bridge (external gfx1 port A)
/0/100/a/0                  bus         ASM1042 SuperSpeed USB Host Controller
/0/100/11                   storage     SB7x0/SB8x0/SB9x0 SATA Controller [IDE mode]
/0/100/12                   bus         SB7x0/SB8x0/SB9x0 USB OHCI0 Controller
/0/100/12.2                 bus         SB7x0/SB8x0/SB9x0 USB EHCI Controller
/0/100/13                   bus         SB7x0/SB8x0/SB9x0 USB OHCI0 Controller
/0/100/13.2                 bus         SB7x0/SB8x0/SB9x0 USB EHCI Controller
/0/100/14                   bus         SBx00 SMBus Controller
/0/100/14.1                 storage     SB7x0/SB8x0/SB9x0 IDE Controller
/0/100/14.2                 multimedia  SBx00 Azalia (Intel HDA)
/0/100/14.3                 bridge      SB7x0/SB8x0/SB9x0 LPC host controller
/0/100/14.4                 bridge      SBx00 PCI to PCI Bridge
/0/100/14.5                 bus         SB7x0/SB8x0/SB9x0 USB OHCI2 Controller
/0/100/15                   bridge      SB700/SB800/SB900 PCI to PCI bridge (PCIE port 0)
/0/100/15.2                 bridge      SB900 PCI to PCI bridge (PCIE port 2)
/0/100/15.2/0               bus         VT6315 Series Firewire Controller
/0/100/15.3                 bridge      SB900 PCI to PCI bridge (PCIE port 3)
/0/100/15.3/0   eth0        network     RTL8111/8168B PCI Express Gigabit Ethernet controller
/0/100/16                   bus         SB7x0/SB8x0/SB9x0 USB OHCI0 Controller
/0/100/16.2                 bus         SB7x0/SB8x0/SB9x0 USB EHCI Controller
/0/101                      bridge      Family 10h Processor HyperTransport Configuration
/0/102                      bridge      Family 10h Processor Address Map
/0/103                      bridge      Family 10h Processor DRAM Controller
/0/104                      bridge      Family 10h Processor Miscellaneous Control
/0/105                      bridge      Family 10h Processor Link Control
/0/1            scsi2       storage     
/0/1/0.0.0      /dev/cdrom  disk        CDDVDW SH-S223Q
/0/2            scsi4       storage     
/0/2/0.0.0      /dev/sda    disk        80GB MAXTOR 4K080H4
/0/2/0.0.0/1    /dev/sda1   volume      66GiB EXT4 volume
/0/2/0.0.0/2    /dev/sda2   volume      8186MiB Extended partition
/0/2/0.0.0/2/5  /dev/sda5   volume      8186MiB Linux swap / Solaris partition
/0/3            scsi6       storage     
/0/3/0.0.0      /dev/sdb    disk        SCSI Disk
/0/3/0.0.1      /dev/sdc    disk        SCSI Disk
/0/3/0.0.2      /dev/sdd    disk        SCSI Disk
/0/3/0.0.3      /dev/sde    disk        SCSI Disk
/1              wlan0       network     Wireless interface

For storage part, ubuntu provides a graphical tool. See "disk utility" on gnome based ubuntu or search for "disk" in launcher.

Set static IP

root@debian:~# cat /etc/network/interfaces
auto lo eth0
iface lo inet loopback
iface eth0 inet dhcp

Now edit the file /etc/network/interfaces 

# The primary network interface
auto eth0
iface eth0 inet static
address 192.168.1.3
gateway 192.168.1.1
netmask 255.255.255.0
network 192.168.1.0
broadcast 192.168.1.255
dns-nameservers 192.168.1.1 8.8.8.8

After it, restart network 

/etc/init.d/networking restart

OR sudo reboot

Note: It does not work by editing /etc/resolv.conf since this file will be overwritten.

Change IP address from the command line

/sbin/ifconfig eth0 192.168.1.17 netmask 255.255.255.0 up
/sbin/ifconfig eth0

Dyndns

See https://help.ubuntu.com/community/DynamicDNS

nano /etc/ddclient.conf 

daemon=600
protocol=dyndns2
use=web, web=checkip.dyndns.com, web-skip='IP Address'
server=members.dyndns.org
login=YOURNAME
password='YOURPASSWORD'
taichi.selfip.net

And run ddclient -daemon=0 -debug -verbose -noquiet to confirm it is working.

webmin

See http://www.webmin.com/deb.html 

wget http://prdownloads.sourceforge.net/webadmin/webmin_1.600_all.deb
dpkg --install webmin_1.600_all.deb

The install will be done automatically to /usr/share/webmin, the administration username set to root and the password to your current root password. You should now be able to login to Webmin at the URL http://localhost:10000/. Or if accessing it remotely, replace localhost with your system's IP address.

Virtual box

Install guest addition for virtualbox on Debian See the link [1] 

apt-get update
apt-get install build-essential module-assistant
m-a prepare
cd Downloads
tar xzvf /media/cdrom0/VMwareTools-9.2.0-799703.tar.gz
cd vmware-tools-distrib
./vmware-install.pl
[Accept all default]
shutdown -r now

virtual machine software benchmark

Emulation vs virtualization

Virtualization allows users to configure virtual machines outfitted with similar hardware and processors as the host system, whereas emulation simulates different hardware and processor configurations in software.

Emulators are what allow you to run old Commodore 64 or NES games on a PC, for example.

Remote desktop connection

  1. Go to System -> Preference -> Remote desktop. Allow other uses to view your desktop & uncheck you must confirm each access & require user to enter this password.
  2. Go to System -> Preference -> Monitor. Change monitor resolution to 1280 x 720.

Instal sshd

apt-get update
apt-get install openssh-server

Install LAMP

See the page [2] 

apt-get install apache2
a2enmod rewrite
apt-get install mysql-server   [I choose branch name as MYSQL root password]
apt-get install php5 php-pear php5-suhosin
apt-get install php5-mysql
/etc/init.d/apache2 restart

Another instruction including how to set up user directories for Apache web server http://wiki.debian.org/LaMp 

apt-get install mysql-server mysql-client
mysql_secure_installation
apt-get install apache2 apache2-doc
apt-get install php5 php5-mysql libapache2-mod-php5
apt-get install python libapache2-mod-python

The apache configuration file is in /etc/apache2/apache2.conf.

For PHP, it is also useful to install php for command line. 

sudo aptitude install php5-cli

Restarting apache before testing on web browser 

/etc/init.d/apache2 restart

Install mediawiki

And also the link http://www.mediawiki.org/wiki/Manual:Running_MediaWiki_on_Debian_GNU/Linux 

aptitude install mediawiki php5 apache2 mediawiki-extensions libapache2-mod-php5

This will install latex. After the end, we can use Synaptic package manager to see what were installed. Now following the instruction in https://help.ubuntu.com/community/MediaWiki, we remove the '#' from the third line so that it reads 'Alias /mediawiki /var/lib/mediawiki': 

sudo nano /etc/mediawiki/apache.conf
sudo /etc/init.d/apache2 restart

Now we can start mediawiki by opening a browser and pointing it to http://localhost/mediawiki.

We need to enter 

Site config
  admin username: WikiSysop
  password:

Database config
  Database name: wikidb
  DB username: 
  DB password: 
  Superuser name: root
  Superuser password: [depend on how it was chosen when installing MYSQL]

Press the button of "Installing mediawiki". We will be welcomed to the wiki page. Following the instruction,

For security reason, I remove new account creation and anonymous editing. I also remove edit counters.

Backup and Restore mediawiki

See docs.google.com note. The process involves 3 parts: mediawiki system, mysql and images.

Install moinmoin

MYSQL security

Just execute mysql_secure_installation from the command line.

  • You can set a password for root accounts.
  • You can remove root accounts that are accessible from outside the local host.
  • You can remove anonymous-user accounts.
  • You can remove the test database, which by default can be accessed by anonymous users.

See http://www.mysql-optimization.com/mysql-secure-installation-program.html

Compiling R

Use the following command to download required components before building any R packages. See also ubuntu package for R 

sudo apt-get build-dep r-base

Package maintenance

https://help.ubuntu.com/community/AptGet/Howto#Maintenance_commands To show package information 

apt-cache show <package_name>

To list files in a package. 

dpkg -L <package_name>

To list racing games package 

apt-cache search racing game

The following command list all packages installed in the system 

apt-cache pkgnames

Remote desktop connection

If vino failed, then try teamviewer. It works fine. After launching it, the software automatically creates an ID and password. We can change the password so it is fixed. Then launch the software on the client. Use the partner's ID and password to connect to it.

View logs

  • Apache /var/log/apache2/access.log

Torrent

Popular search sites

  • torrentz
  • thepiratebay
  • isohunt
  • kickass torrents

Torrent client: transmission-cli

Torrent client: rtorrent

Install webmin

apt-get install perl libnet-ssleay-perl openssl libauthen-pam-perl libpam-runtime libio-pty-perl apt-show-versions python
wget http://prdownloads.sourceforge.net/webadmin/webmin_1.600_all.deb
dpkg --install webmin_1.600_all.deb

Webmin.png

File does not exist: /var/www/favicon.ico from /var/log/apache2/error.log

The reason? You have not created a favicon, also known as a website icon, for your website. It’s the icon that displays in the address bar of your web browser when you connect to a website. A web browser will request this icon file from every website.

If you choose to create one. Use a program such as Gimp and create a 16×16 pixel image and save it as a .ico filetype. Then upload that file to the DocumentRoot of your website. You will need one for each VirtualHost. If you don’t have Gimp, there are online resources such as favicon.cc where you can create a .ico file and download it for your own use.

As you know by now, not having a favicon.ico file, won’t stop web browsers from requesting it each time. But you can tell Apache not to log the event as an error message. You will still see the request in the access.log, but at least you will have a cleaner error.log file.

Add the following block of code to each VirtualHost, or at least the ones which don’t have a favicon file. 

Redirect 404 /favicon.ico
<Location /favicon.ico>
 ErrorDocument 404 "No favicon"
</Location>

Don’t forget to restart apache after making the change. If you want make a “global” change, which would apply to any and all VirtualHosts, you can create a file in Apache’s conf.d folder with a name such as nofavicon.conf and then add that block of code to the file. That would disable favicon across the board and save you from having to edit each VirtualHost.

Or, you create an empty file with the name “favicon.ico” in the directory root of Apache (for exemple /var/www/).

Show weather on the taskbar

http://www.noobslab.com/2012/10/important-thingstweaks-to-do-after.html

Screencaster

kazam

Watch TV

Freetuxtv

Running concrete5 On Nginx (LEMP)

http://www.howtoforge.com/running-concrete5-on-nginx-lemp-on-debian-squeeze-ubuntu-12.10

Download mms stream (simple & stable)

  • Use mimms (will NOT output to speaker at the same time; so is best in terms of performance)
sudo apt-get install mimms
mimms -t 60 mms://example.com/video

where -t option specifies number of minutes. See http://linuxers.org/howto/how-download-mms-streaming-videos-ubuntu The output will have the same extension as the input. But it is not always clear. For example 

$ mimms -t 3 mms://bcr.media.hinet.net/RA000073                                                                                                    
mms://bcr.media.hinet.net/RA000073 => RA000073.wmv
1.48 MB / ∞ B (8.79 kB/s, ∞ s remaining)           
Download stopped after user-specified timeout.


  • Use mplayer (will output to speaker at the same time, so suffer from performance, anyway do not get output)
mplayer mms:/link/something.xxx -dumpstream -dumpfile file.xxx

mms:/link/something.xxx - link to the stream you wish to download file.xxx - file to which you wish to download the stream, be careful to write the same extension xxx

Wait for the file to download and that's it. See http://ubuntuhowtos.com/howtos/download_mms_stream

Use VLC to record internet radio (not stable & complicated)

sudo apt-get install ubuntu-restricted-extras

sudo apt-get install lame  libmp3lame0
sudo apt-get install ffmpeg
sudo apt-get install libavcodec-extra-53 libavdevice-extra-53 libavfilter-extra-2 libavformat-extra-53 libavutil-extra-51 libpostproc-extra-52 libswscale-extra-2

A successful run will have an output like 

VLC media player 2.0.3 Twoflower (revision 2.0.2-93-g77aa89e)
[0x2329ca8] dummy interface: using the dummy interface module...
[0x7fac2c007428] mux_dummy mux: Open
[0x7fac2c003598] access_mms access: selecting stream[0x1] audio (39 Kib/s)
[0x7fac2c003598] access_mms access: connection successful
[0x7fac2c003598] access_mms access error: failed to send command
[0x7fac2c005fe8] idummy demux: command `quit'

RHEL/CentOS

What is my IP address

ifconfig eth0

What is my DNS server

/etc/resolv.conf

What services get started at boot time

chkconfig --list

Is xxx service running

xxx status

What services are currently running

ps -e

and 

lsof -i

will show you services that are listening to TCP or UDP endpoints.

What network ports are open

lsof -i

or 

netstat -aut

What firewall rules do I in place

iptables -L

What packages do I have installed

rpm -qa | less

or 

rpm -qa | grep xxx

What version of package xxx do I have installed

rpm -qi xxx

List of available (uninstalled) packages

yum list available
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