Tag Archives: unix

Unix: Print Directory Tree Structure

shell script

The tree command has been around in Windows for a very long time to print out the directory structure but this is still not available in most of the Unix variants. Most of the new Linux distributions do seem to have the tree command available.

Special Shell Variables

As I always have a tendency to forget the special variables used in shell scripts, I am going to document down the variables here.

Shell Script with Password Prompt

shell script

At work, I have a couple of shell scripts to perform LDAP queries. Initially the scripts were hard-coded with the login credentials of a read-only user. But as the scripts were enhanced to handle LDAP query updates, I realised that it was not a good idea anymore to hard-code the username and password as I was just inviting trouble. And the scripts will be a big NO during system audit.

Shell Script: Check If Weekend

I have some shell scripts that will perform certain actions only on a weekend (Saturday or Sunday). There are two ways to solve the “is it a weekend” logic.

Create a tar.gz File in a Single Command in Solaris

Solaris does not ship with the GNU tar and by default, the tar command in Solaris does not allow you to create gzip or bzip2 files, but only pure tarballs. You will need to create a tar file first and then compress the tarball with the gzip command.

K, Ki Key Conversion Tool for AUC / HLR

I have been looking for a tool to encrypt Ki values (into eKi) using AES encryption. Ki is a 128-bit value used in authenticating the SIMs on the mobile network.

How to Get the Home Directory of an User

To perform disk usage monitoring of users on a UNIX system, you will, first of all, need to determine the home directories of the users. You might ask, “Aren’t all the user home directories found under /home?”. Well, typically yes, but it’s not always true.

How to Perform Reverse DNS Lookup

unix linux

Everyone knows that DNS is used to translate hostnames to IP addresses, but do you know that DNS can also be used to retrieve the domain name when the IP address is known?

Transfer Files Using Netcat

unix linux

Netcat is often known as the swiff army knife for TCP/IP. It’s features include but not limited to UDP/TCP port scanning, file transfers, tunneling of UDP over TCP, port forwarding and so on.