Archive for January, 2009

• TECHPULP | What is DMZ network and why is it needed
  In networking terminology, the DMZ network is defined as a network which is less restricted as opposed to corporate network (LAN) which can never be accessible to outside world directly. It is always recommended that all public servers like web...
• TECHPULP | How to verify the integrity of a large downloaded file
  There are some algorithms like MD5 and SHA1 which generate unique digest for any given input. Basic idea is to find the MD5 or SHA1 digest of the file which is going to be downloaded and cross check the same...

• TECHPULP | How to monitor all processes in a Linux/UNIX system
  The Linux system provides a command called “top” which provides dynamic real-time view of running processes, memory status, cpu usage and other system information. This command is very easy to use and it updates the display automatically and user just...
• TECHPULP | How to see last login records of a user in Linux
  The Linux system stores login attempts of all users in a file called “wtmp“. Typically this file will be located in “/var/log” directory. The Linux command line utility “last” can be used to list the currently logged in users as...

• TECHPULP | How to list hidden files in Linux/UNIX
  Any hidden file or directory in UNIX/Linux systems start with period (.) character. The standard usage of “ls” skips the hidden files and directories from display. However if you would like to view hidden ones as well, the “ls” command...
• TECHPULP | How to check if a Bash variable is set or not
  There is no direct method in bash to determine if a variable is set or not. But we can use “parameter expansion” feature provided by bash. The following example script determines if bash variables MYVAR and MYVAR1 are set or...

• TECHPULP | How to change a file’s modification date and time
  Typically, for each file or a directory, the Linux/Unix system maintains three time stamps: “Access”, “Modify” and “Change”. The command “stat” can be used to get the information as shown below. [neo@techpulp ~]# stat face.jpg File: `face.jpg' Size: 3689673         Blocks:...
• TECHPULP | How to determine type of a file in Linux
  The command “file” tells you the file type and format. It maintains loads of magics in its database to identify the type of a file.  If it can’t determine the file type, it will display whether it is an ASCII...

• TECHPULP | How to find how much disk space a directory is consuming in Linux
  The Linux command line utility “du” (disk usage) tells you how much space a file or a directory is taking on the disk. Just run the command against a file or a directory. If a directory is specified it determines...
• TECHPULP | How to disable Ads using HOSTS file in Microsoft Windows/Linux/UNIX
  One way of avoiding online advertisements is to redirect all requests to Ad sites to locahost so that bandwidth is well utilized. It also results in faster browsing as it eliminates Domain Name Service (DNS) requests. For this you need...