Category Archives: Linux

Unix: How to Install BerkeleyDB From Source

Posted on July 23, 2010 by Masao

This documentation is buried in the source as HTML, so I’m posting it here for convenience. Building for UNIX/POSIX The Berkeley DB distribution builds up to four separate libraries: the base C API Berkeley DB library and the optional C++, … Continue reading →

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Ubuntu: Flushing IpTables Causes Loss of Internet Connection

Posted on July 21, 2010 by Masao

If you are trying to disable the firewall, but lose Internet connection in the process, use this script: iptables -F iptables -X iptables -t nat -F iptables -t nat -X iptables -t mangle -F iptables -t mangle -X iptables -P … Continue reading →

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Linux: How To Edit resolv.conf Using dhclient.conf

Posted on July 15, 2010 by Masao

So, you’re trying to get here: /etc/resolv.conf: nameserver 192.168.1.1 domain aaa.com search aaa.com bbb.com You need to edit dhclient.conf like this: /etc/dhcp3/dhclient.conf: supersede domain-name-servers 192.168.1.1; supersede domain-name “aaa.com”; append domain-name ” bbb.com”; There must be a space before the bbb.com … Continue reading →

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Ubuntu: How To Enable Sound

Posted on July 8, 2010 by Masao

HP xw6400 Workstation: How to fix your machine if your speakers don’t work. Determine your sound card model: cat /proc/asound/card0/codec#* | grep Codec Look up the model in this list: http://www.kernel.org/doc/Documentation/sound/alsa/HD-Audio-Models.txt Edit your ALSA (Advanced Linux Sound Architecture) conf file: … Continue reading →

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Ubuntu: How to Determine Motherboard Type

Posted on July 8, 2010 by Masao

lshw – list hardware sudo lshw lspci – list all PCI devices sudo lspci

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Ubuntu: APT and DPKG

Posted on July 2, 2010 by Masao

How to display the files of a package installed? To list all the files provided by the installed package foo execute the command dpkg –listfiles foo Note that the files created by the installation scripts aren’t displayed. http://www.debian.org/doc/FAQ/ch-pkgtools.en.html

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Fedora: How To Flush DNS Cache

Posted on June 27, 2010 by Masao

nscd -i hosts

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Ubuntu: Show Dynamic Title in Terminal

Posted on June 22, 2010 by Masao

A quick solution to this problem is to make sure that /etc/bash.bashrc file has a line uncommented. vim /etc/bash.bashrc Then, look for this line and make sure it is NOT commented out: PROMPT_COMMAND=’echo -ne “\033]0;{USER}@${HOSTNAME}: ${PWD}\007″‘

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Ubuntu: Workplace Switcher Labels

Posted on June 18, 2010 by Masao

By default, you can’t add labels in the workplace switcher in Ubuntu. To enable them, go to System > Preferences > Appearance. Click the Visual Effects tab. Then, click None, to disable all effects. Now, you should be able to … Continue reading →

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How to Edit resolv.conf Permanently

Posted on June 16, 2010 by Masao

Edit this file: # vim /etc/dhcp3/dhclient.conf To append a search domain, add this to the file: append domain-name ” mycrazydomain.com”; …which will allow your machine to search *.mycrazydomain.com. Note the initial space within the double quotes. Then run: # /sbin/dhclient … Continue reading →

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Linux Screen Basics

Posted on April 23, 2010 by Masao

CTRL-A : screen command mode CTRL-A ” ” : show list CTRL-A SHIFT-A : rename this screen session CTRL-A n : next screen CTRL-A p : previous screen CTRL-A M : monitor for activity CTRL-A _ : monitor for silence … Continue reading →

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How To Fix "The total number of locks exceeds the lock table size"

Posted on March 4, 2010 by Masao

This usually happens when you’re doing massive queries on InnoDB tables: ERROR 1206 (HY000): The total number of locks exceeds the lock table size In /etc/my.cnf, do something like this: innodb_buffer_pool_size=524288000 By default, MySQL sets innodb_buffer_pool_size to 8MB. 500 megabytes … Continue reading →

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How To Fix "Metadata file does not match checksum" YUM error

Posted on December 30, 2009 by Masao

# yum install -y ImageMagick-perl Loaded plugins: fastestmirror Setting up Install Process Parsing package install arguments Resolving Dependencies –> Running transaction check —> Package ImageMagick-perl.i386 0:6.2.8.0-4.el5_1.1 set to be updated filelists.xml.gz | 3.9 MB 00:09 http://apt.sw.be/redhat/el5/en/i386/rpmforge/repodata/filelists.xml.gz: [Errno -1] Metadata file … Continue reading →

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How to Install Flash Firefox Plugin for 64-bit Fedora Linux

Posted on September 13, 2009 by Masao

Download the plugin here. Tar -zxvf the tar.gz file. Copy that file to: /usr/lib64/mozilla/plugins Restart firefox. Check “about:plugins” in your address bar to see the Flash plugin installed Plugin file should look like this: /usr/lib64/mozilla/plugins/libflashplayer.so about:plugins should look like this: … Continue reading →

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How To Determine Directory of Sourced Bash Script

Posted on September 2, 2009 by Masao

Sourcing a script can be useful for exporting variables in the current shell. However, you can’t use “dirname $0″ to get the directory of the script. Here’s how to get the same effect of dirname, but still allowing you to … Continue reading →

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How to Fix an Empty Bash Shell Prompt

Posted on August 21, 2009 by Masao

If you bash shell prompt is empty when logging in, here’s how to fix it. Create a ~/.bashrc file: if [ -f /etc/bashrc ]; then . /etc/bashrc fi Create a ~/.bash_profile file: if [ -f ~/.bashrc ]; then . ~/.bashrc … Continue reading →

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How To Know If You Have a 64-bit Processor

Posted on August 5, 2009 by Masao

If you have asked yourself, “Do I have a 64-bit processor?”, then here are several ways to find out: uname # uname -p x86_64 cpuinfo # cat /proc/cpuinfo flags : fpu vme de pse tsc msr pae mce cx8 apic … Continue reading →

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How to fix: error while loading shared libraries: liblwres.so.50

Posted on July 16, 2009 by Masao

To fix this error: # nslookup mydomain.com nslookup: error while loading shared libraries: liblwres.so.50: cannot open shared object file: No such file or directory Do this: # ldconfig # dig mydomain.com ; DiG 9.6.1-RedHat-9.6.1-2.fc11 mydomain.com … From the ldconfig manpage: … Continue reading →

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How to Check Disk Speed on Linux

Posted on June 26, 2009 by Masao

/sbin/hdparm -tT /dev/sda

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How to Fix "SSH Public Key Authentication Failed"

Posted on June 3, 2009 by Masao

If your SSH public key authentication is failing with errors like this: $ ssh -vvv myhost.com debug3: authmethod_is_enabled publickey debug1: Next authentication method: publickey debug1: Offering public key: /home/kitamura/.ssh/id_dsa debug3: send_pubkey_test debug2: we sent a publickey packet, wait for reply … Continue reading →

Posted in Linux, SSH, Troubleshooting | 1 Comment