Search and Replace large files inplace

using sed

find /path/to/files -type f -exec sed -i 's/fromString/toString/g' {} \;

using perl

find /path/to/files -type f -exec perl -pi -e  's/fromString/toString/g' {} \;

Command to see CDP packets and identify the cisco switch and port your machine is connected to

# tcpdump -nn -vvv -i eth0 -s 1500 -c 1 'ether[20:2] == 0x2000'

Screen Capture Fedora

For screen capture with audio I have used gtk-RecordMyDesktop

# yum install gtk-recordmydesktop

Options for selecting window or fullscreen are available.

Description of the system’s hardware components - Linux

# dmidecode | less

TOra For Database Development

TOra

TOra is an open-source multi-platform database management GUI that supports accessing most of the common database platforms in use, including Oracle, MySQL, and Postgres, as well as limited support for any target that can be accessed through Qt's ODBC support. TOra has been built for various Linux distributions, Mac OS X, MS Windows, and UNIX platforms.

Set Up an Email Gateway with CentOS Linux�5.4 � Aaron Walrath – Another IT Guy's Meanderings

A very useful mail gateway setup on Linux to be an edge server for MS Exchange.

Set Up an Email Gateway with CentOS Linux�5.4 � Aaron Walrath – Another IT Guy's Meanderings

Heartbeat on CentOS

When you try to install heartbeat using yum when the dependencies are not installed you get the following error.

yum -y install heartbeat

useradd: user hacluster exists
error: %pre(heartbeat-2.1.3-3.el5.centos.x86_64) scriptlet failed, exit status 9
error:   install: %pre scriptlet failed (2), skipping heartbeat-2.1.3-3.el5.centos

Due to this error heartbeat is not installed.

A simple fix is install heartbeat again using yum and that should solve the problem until someone upstream fixes the installer.