Linux
Not-so-obvious Linux tips
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.
Debian/Ubuntu
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 192.168.0.100 gateway 192.168.0.1 netmask 255.255.255.0 network 192.168.0.0 broadcast 192.168.0.255
After it, restart network
/etc/init.d/networking restart
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.
Install guest addition for virtualbox
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
Remote desktop connection
- 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.
- 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.
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,
Backup and Restore mediawiki
See docs.google.com note. The process involves 3 parts: mediawiki system, mysql and images.
Install moinmoin
- Comparison of mediawiki vs moinmoin http://www.wikimatrix.org/compare/MediaWiki+MoinMoin
- Comparison of wiki software http://en.wikipedia.org/wiki/Comparison_of_wiki_software
- Moinmoin website http://moinmo.in/
- moinmoin was used by Bioconductor, ubuntu, etc.
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
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
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/).
RHEL/CentOS
Pogoplug
Install ArchLinux on pogoplug (Debian is better actually)
See the instruction in http://archlinuxarm.org/platforms/armv5/pogoplug-v2-pinkgray for how to install Archlinux on pogoplug (E02). I make a copy below.
killall hbwd cd /tmp wget http://jeff.doozan.com/debian/uboot/install_uboot_mtd0.sh chmod +x install_uboot_mtd0.sh ./install_uboot_mtd0.sh /sbin/fdisk /dev/sda
At the fdisk prompt, delete old partitions and create a new one:
- Type o. This will clear out any partitions on the drive.
- Type p to list partitions. There should be no partitions left.
- Now type n, then p for primary, 1 for the first partition on the drive, and then press ENTER, accepting default values.
- Exit by typing w.
wget http://archlinuxarm.org/os/pogoplug/mke2fs chmod 755 mke2fs ./mke2fs /dev/sda1 mkdir usb mount /dev/sda1 usb cd usb wget http://archlinuxarm.org/os/ArchLinuxARM-armv5te-latest.tar.gz tar -xzvf ArchLinuxARM-armv5te-*.tar.gz # This will take a long time rm ArchLinuxARM-armv5te-*.tar.gz sync # Takes a while when using a flash drive. Not in my case however. cd .. umount usb /sbin/reboot
Log back in after your Pogoplug reboots using username root and password root.
At the end, the system is very lean.
[root@alarm ~]# free
total used free shared buffers cached
Mem: 252492 28292 224200 0 4580 14072
-/+ buffers/cache: 9640 242852
Swap: 0 0 0
[root@alarm ~]# df -lh
Filesystem Size Used Avail Use% Mounted on
rootfs 7.4G 443M 6.6G 7% /
/dev/root 7.4G 443M 6.6G 7% /
devtmpfs 124M 0 124M 0% /dev
run 124M 224K 124M 1% /run
shm 124M 0 124M 0% /dev/shm
tmpfs 124M 0 124M 0% /tmp
[root@alarm ~]# uname -a
Linux alarm 3.1.10-13-ARCH #1 PREEMPT Mon Aug 20 15:46:18 UTC 2012 armv5tel GNU/Linux
[root@alarm ~]# cat /proc/cpuinfo
Processor : Feroceon 88FR131 rev 1 (v5l)
BogoMIPS : 1191.11
Features : swp half thumb fastmult edsp
CPU implementer : 0x56
CPU architecture: 5TE
CPU variant : 0x2
CPU part : 0x131
CPU revision : 1
Hardware : Marvell SheevaPlug Reference Board
Revision : 0000
Serial : 0000000000000000
[root@alarm ~]# cat /proc/cpuinfo
Processor : Feroceon 88FR131 rev 1 (v5l)
BogoMIPS : 1191.11
Features : swp half thumb fastmult edsp
CPU implementer : 0x56
CPU architecture: 5TE
CPU variant : 0x2
CPU part : 0x131
CPU revision : 1
Hardware : Marvell SheevaPlug Reference Board
Revision : 0000
Serial : 0000000000000000
[root@alarm ~]#
After it, follow the instruction on lifehacker and https://wiki.archlinux.org/index.php/DeveloperWiki:usrlib
pacman -Syu --ignore glibc pacman -Su mkinitcpio -p linux
To install rsync, use
pacman -S rsync
Unfortunately, I cannot bypass the error
[root@alarm ~]# pacman -Suy rsync :: Synchronizing package databases... core is up to date extra is up to date community is up to date alarm is up to date aur is up to date :: Starting full system upgrade... resolving dependencies... looking for inter-conflicts... Targets (2): glibc-2.16.0-4 rsync-3.0.9-5 Total Installed Size: 34.26 MiB Net Upgrade Size: 0.61 MiB Proceed with installation? [Y/n] (2/2) checking package integrity [#############################] 100% (2/2) loading package files [#############################] 100% (2/2) checking for file conflicts [#############################] 100% error: failed to commit transaction (conflicting files) glibc: /lib exists in filesystem Errors occurred, no packages were upgraded.
Install Debian on pogoplug
See the instruction on http://projects.doozan.com/debian.
- Find your devices's IP address and connect via SSH:
- Partition your flash drive with fdisk:
fdisk /dev/sda # Configure partion 1 as Linux (I'd recommend making this at least 512Mb. The default bare-bones installation uses 280Mb.) # Configure partion 2 as Linux Swap (I used 256MB. Adjust according to your anticipated memory usage.) # Set partition 1 active
- Download and run the Debian Wheezy installer:
cd /tmp wget http://projects.doozan.com/debian/kirkwood.debian-wheezy.sh chmod +x kirkwood.debian-wheezy.sh export PATH=$PATH:/usr/sbin:/sbin ./kirkwood.debian-wheezy.sh
- Alternatively, you can choose to install Debian Squeeze with the following commands:
cd /tmp wget http://projects.doozan.com/debian/dockstar.debian-squeeze.sh chmod +x dockstar.debian-squeeze.sh export PATH=$PATH:/usr/sbin:/sbin ./dockstar.debian-squeeze.sh
The script will take some time to download the debian images and extract them to your flash drive. The total install time will vary with the speed of your flash drive and your Internet connection. On my system, it takes about 20 minutes. Once it's finished, you can reboot into your new Debian install.
After your device reboots, it may have a different IP address (it's identifying as 'Debian' to the DHCP server now instead of 'Pogoplug').
The default root password in Debian is 'root'. After you've logged in, you should change the root password and configure /etc/apt/sources.list to point to a Debian mirror near you.
passwd nano /etc/apt/sources.list
After reboot, the debian system is very lean too
root@debian:~# df -h
Filesystem Size Used Avail Use% Mounted on
rootfs 3.2G 260M 2.8G 9% /
none 123M 36K 123M 1% /dev
/dev/sda1 3.2G 260M 2.8G 9% /
tmpfs 125M 0 125M 0% /lib/init/rw
tmpfs 125M 0 125M 0% /dev/shm
tmpfs 125M 0 125M 0% /tmp
root@debian:~# free
total used free shared buffers cached
Mem: 255672 19636 236036 0 816 11104
-/+ buffers/cache: 7716 247956
Swap: 535544 0 535544
After I install LAMP, the memory uses 250MB. However, after I reboot the pogoplug, it reduces to 66MB.
root@debian:~# free
total used free shared buffers cached
Mem: 255672 66076 189596 0 1244 37000
-/+ buffers/cache: 27832 227840
Swap: 535544 0 535544
Other resources: