Sometime when you have two network interfaces (say
eth1) on the client and for some reason there is a need to SSH to the server over a specific a specific interface. By default the primary interface will be used. To use eth1 we just need to add a route:
route add -net 10.75.0.0 netmask 255.255.255.0 gw 192.168.0.1 eth1
The route is removed upon reboot. Use -p to permanently add the route to the table. To delete the route:
route del -net 10.75.0.0 netmask 255.255.255.0 gw 192.168.0.1 eth1
If you’re anything like me, you probably log in and out of a half dozen remote servers (or these days, local virtual machines) on a daily basis. And if you’re even more like me, you have trouble remembering all of the various usernames, remote addresses and command line options for things like specifying a non-standard connection port or forwarding local ports to the remote machine.
Here’s a simple guide showing how you can enable HTTP/2 in Apache on Ubuntu 16.04.
Today’s internet connections are amazingly fast. You younglings might not believe this, but there was a time when we actually had to sit and wait for a website to appear. If you want to experience the internet speeds of the past, give 56k Emulator a try. It will give you the basic idea. And keep in mind that 56K modems were freakin’ fast when they became available.
Even though today’s internet connections are fast, the technology used to push propaganda around inside the tubes is old and slow. HTTP/1.1 was never intended to be used with the kind of content-heavy website we have today. Thankfully, there’s a new option available, the marvelous RFC-7540. Or HTTP/2, if you will.
In Unix and Unix-like systems (like Ubuntu), archiving and compression are separate.
tar puts multiple files into a single (tar) file.
gzip compresses one file (only).
So to get a compressed archive, you combine the two, first use
pax to get all files into a single file (archive.tar), then
gzip it (archive.tar.gz). If you only have one file you need to compress (notes.txt), there’s no need for tar, so you just do
gzip notes.txt which will result in
notes.txt.gz. There are other types of compression, such as
xz which work in the same manner as gzip (apart from using different types of compression of course)
LT2P IPSEC vpn works simple and easily with iOS/Android and Windows 10. Unfortunately as many people likely know (after a few google searches it seems) the client for this is pretty crap in Ubuntu 16.04.
Our setup uses a shared PSK, and a username and password.
I’ve tried a bunch of the quick setup guides, but many were for older versions of Ubuntu and thus didn’t work very well. Finally I stumbled across this guide: https://gist.github.com/psanford/42c550a1a6ad3cb70b13e4aaa94ddb1c
which was used to connect with a meraki router over vpn. There were some minor tweaks in my case, but I managed to get it work.
To perform a global search and replace in vim, use the search and replace command in command mode:
% is a shortcut that tells vi to search all lines of the file for
search_string and change it to
replacement_string. The global (
g) flag at the end of the command tells vi to continue searching for other occurrences of
search_string. To confirm each replacement, add the confirm (
c) flag after the global flag.
Setting the NLS_LANG Environment Variable for Oracle Databases:
It would also be advisable to set env variable in your
.bash_profile [on start up script]
This is the place where other ORACLE env variables (ORACLE_SID, ORACLE_HOME) are usually set.
First of all you need to download Instant Client Downloads. Install alien software so you can install rpm packages by typing following command in terminal.
sudo apt-get install alien
Once that is done, go to the folder where the rpm files are located and execute the following:
Compress an Entire Directory or a Single File
Use the following command to compress an entire directory or a single file on Linux. It’ll also compress every other directory inside a directory you specify–in other words, it works recursively.
tar -czvf name-of-archive.tar.gz /path/to/directory-or-file
Here’s what those switches actually mean:
- -c: Create an archive.
- -z: Compress the archive with gzip.
- -v: Display progress in the terminal while creating the archive, also known as “verbose” mode. The v is always optional in these commands, but it’s helpful.
- -f: Allows you to specify the filename of the archive.
macOS Sierra 10.12.0
sudo killall -HUP mDNSResponder
Linux (depending on what you’re running)