Howto

How to colorizing cat command output or files using ccat app on Linux or Unix system

Posted on in Categories Command Line Hacks, Howto last updated August 30, 2017

The [nixcmd name="cat"] (short for concatenate) is one of the most frequently used flexible commands on Linux, Apple MacOS X, *BSD (FreeBSD / OpenBSD / NetBSD), Unix-like operating systems. It is useful to display text files on screen, copy text files, combine text files, create new text files and more. If you cat command with colours, try ccat app.

I put a cronjob in /etc/cron.{hourly,daily,weekly,monthly} and it does not run and how can I troubleshoot it?

Posted on in Categories Cloud Computing, Howto, Open Source, Web Developer last updated August 27, 2017


Recently I created a simple shell script called backup.sh in /root/scripts directory to just backup MySQL database and dumped it to /nfs/mysql/ directory. I put a file (more like used the ln command to create a soft link ) in /etc/cron.hourly/ and it doesn’t run. There was no error in systemd log or cron log. Why is my cron job was not working, and here is how I troubleshoot it.

OpenSSL drops TLS 1.0/1.1 support for Debian Unstable and what does it mean for Debian sid users?

Posted on in Categories Debian Linux last updated August 7, 2017

From the announcement mailing list:

I’ve just uploaded a version of OpenSSL to unstable that disables the TLS 1.0 and 1.1 protocol. This currently leaves TLS 1.2 as the only supported SSL/TLS protocol version.

This will likely break certain things that for whatever reason still don’t support TLS 1.2. I strongly suggest that if it’s not supported that you add support for it, or get the other side to add support for it.

OpenSSL made a release 5 years ago that supported TLS 1.2. The current support of the server side seems to be around 90%. I hope that by the time Buster releases the support for TLS 1.2 will be high enough that I don’t need to enable them again.

neofetch: Awesome system info bash script that supports Linux, MacOS, and Unix-like systems

Posted on in Categories Command Line Hacks, Howto last updated May 7, 2017

The neofetch command written in a bash shell. The main purpose of neofetch is to be used in screenshots to display other users what operating system or Linux distro you are using including theme, icons and more. This command shows info about your system next to an image, your operating system logo and other info. Neofetch version 3.1.0 has been released. Let us see how to install the latest version and use it.
Continue reading “neofetch: Awesome system info bash script that supports Linux, MacOS, and Unix-like systems”

How to enable Wake on Lan (WOL) with Advanced TomatoUSB wifi router firmware

Posted on in Categories Hardware, Howto, Networking, Open Source last updated March 29, 2017

I recently installed TomatoUSB advanced firmware on my Asus RT-AC66U wifi router. This router act as my wireless Ethernet bridge. TomatoUSB advanced has additional features like

  • SSH
  • Multiple WAN support (3G/4G/Static IP/Cable/ADSL2)
  • Tor
  • Virtual Wireless
  • DMZ
  • IPv6
  • FTP/Media server via USB
  • BiTorrent Client via USB
  • UPS support
  • OpenVPN client and server
  • Tinc VPN server and much more.

How to use parallel ssh (PSSH) for executing ssh in parallel on a number of Linux/Unix/BSD servers

Posted on in Categories Cloud Computing, Command Line Hacks, Howto last updated April 21, 2017

Recently I come across a nice little nifty tool called pssh to run a single command on multiple Linux / UNIX / BSD servers. You can easily increase your productivy with this SSH tool.

More about pssh

pssh is a command line tool for executing ssh in parallel on some hosts. It provides specialties includes:

  1. Sending input to all of the processes
  2. Inputting a password to ssh
  3. Saving output to files
  4. IT/sysadmin taks automation such as patching servers
  5. Timing out and more

Let us see how to install and use pssh on Linux and Unix-like system.

pssh-welcome

How to protects Linux and Unix machines from accidental shutdowns/reboots with molly-guard

Posted on in Categories Command Line Hacks, Debian Linux, Hardware last updated February 19, 2017

Oops! I did it again. I thought I was logged into my home server. Turns out I rebooted the db server. Another my not so favorite is typing “shutdown -h 0” into the wrong terminal. I know a few people who have admitted to doing that here.

My anger that can't be contained
Is there any end to the madness? Do I need to suffer from accidentally random reboots and shutdowns? After all, it is human nature to make mistakes, but one should not keep on making the same mistakes again and again.