Systems Administration
Posted Wed, 2009-06-10 11:04 by geekwisdom
We've all experienced it. We want to unmount something and the device is busy. Enter the lazy switch for the umount command.
umount -l /dev/
As soon as the last process stops using the device it gets unmounted. Many times this happens instantly.
Posted Mon, 2009-05-11 01:13 by geekwisdom
For the last month or so I've been experiencing sec_error_crl_invalid errors on a couple of sites when using Firefox 3. Thanks to this post on NZGeek's blog I was able to resolve the issue. It turns out by deleting the CRLs (that where disabled anyway) I was able to solve my issue.
Posted Thu, 2009-03-26 09:34 by geekwisdom
I want to do virtual hosting of SSL-enabled virtual hosts on the same Apache server as my other non-SSL-enabled virtual hosts. I don't want to assign more than one IP address to the server and all of my virtual hosts will be within the same domain (e.g., example.com).
BACKGROUND
When Apache processes a request for a name-based virtual host it receives the request from the browser, which includes the Host header (e.g., Host: www.example.com). Apache uses the Host header to determine which name-based virtual host to route the request to. It works this way regardless of the connection type, HTTP or HTTPS.
Posted Fri, 2009-03-06 15:35 by geekwisdom
Unless you have intelligent backup software that can do something smart to backup your databases, restoring a backup of a running MySQL server is like restarting your database after a hard system crash, it's a crap shoot. Since I don't have any fancy backup software that can help I decided to use mysqldump to create a snapshot of my database server and write it out to a compressed SQL file. Then my (dumb) backup software can continue to be used and I will be able to recover easily if my server dies.
Here's the quick and dirty script:
#!/bin/sh
#
# This script automates a call to mysqldump
# and sends the output to a file in a backup
# directory. The script is set up to keep
# seven days of history.
#
# Before you can run this script you must
# set up a MySQL user that can perform the
# backup. This user must have permission to
# SELECT and LOCK TABLES. The user should not
# be permitted to access MySQL in any way other
# than through the local socket. Here's how the
# user should be created:
#
# GRANT SELECT,LOCK TABLES ON *.* TO 'SomeUser'@'localhost' IDENTIFIED BY 'SomePassword'
# FLUSH PRIVILEGES;
#
# This script should be owned by root and only
# root should be able to read, write, and
# execute it. (i.e., chmod 700)
#
Posted Wed, 2009-03-04 14:46 by geekwisdom
I recently had to upgrade a moldy old MySQL database server from version 3.23 to 5.0.x. Instead of stepping from 3.23 to 4.0, then from 4.0 to 4.1, and finally from 4.1 to 5.0.x I decided to use mysqldump.
I ran the following command on the old database server:
/path/to/mysqldump -u root -p -h oldserver.example.com --opt --all-databases > bigdump.sql
Then all I had to do was move the bigdump.sql file over to the new server and run the following command:
/path/to/mysql -u root -p -h newserver.example.com < bigdump.sql
Now all that is necessary is to flush the privileges so that users can access the databases. I logged into MySQL:
/path/to/mysql -u root -p -h newserver.example.com mysql
Posted Fri, 2008-09-05 13:51 by geekwisdom
perl -wne'while(/[\w\.\-]+@[\w\.\-]+\w+/g){print "$&\n"}' BigFileContainingEmails.txt | sort -u > output.txt
Posted Mon, 2008-05-12 15:07 by wartex8
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