Ubuntu Linux: Turn On Exec-Shield Buffer Overflow Protection

I am trying to set exec-shield protection on Linux as described here but getting the following error on Ubuntu Linux server version 12.04 LTS: sysctl -w kernel.exec-shield=1 error: “kernel.exec-shield” is an unknown key How do…

Unix and Linux: Redirect Error Output To null Command

I ‘m a new Linux system user. How can I redirect command error output /dev/null on a Linux or Unix-like system using Bash shell?   Your shell comes with three file descriptors as follows: stdin…

sed Tip: Delete All Blank White Spaces

I have a text file as follows: foo bar foobar How can I delete all leading and/or trailing blank spaces, tab from each line using sed command?   You can use sed command to delete…

Debian 7 Wheezy: Install Flash Player

I am a new Debian Linux version 7 user. I found out that Pandora player is not working due to Adobe flash player. How do I install and use flash player on Debian 7 with…

Mac OS X: Install GCC Compiler with Xcode

I have Mac OS X Mountain Lion. I need to compile a few apps and Perl modules. Then I already installed Xcode from app store but I’m unable to find gcc compiler or make command.…

CentOS / RHEL: Check If A Service Is Running Or Not

How do I find out if a service such as MySQL or Apache running on my Centos/RHEL/Fedora Linux server? You need to use service command. It runs a System V init script in as predictable…

Mac OS X: Wake Up Servers Using Wake-on-LAN ( WOL ) Command Utility

I know how to send WOL command using Linux or FreeBSD wake command. But, how do I send Wake on LAN (WOL) frames to hosts on a local Ethernet network using Apple OS X Unix…

Linux: Find Out Directory Size Command

I am a new Linux user. How do I find out size of a directory on Linux operating systems using command line options?   You need to use the du command: [a] Find and estimate…

Linux: Find Out How Much Disk Space Left On Hard Drive

I am a desktop support professional with experience working in a corporate call center environment. Recently, I started to admin RHEL based IBM Linux server. How do I determine how much disk space left in…

Mac Os X: Find Out Wireless WI-Fi Connection Speed Rate

H ow do I see my current WI-FI (Wifi) connection speed in Apple Mac OS X?   WI-FI allows an electronic device such as Apple laptop, ipad, iPhone and other iDevices to exchange data or…