System Administration on Aamnah - Frontend Web Developer

Connect from macOS to Ubuntu remote desktop using xfreerdp and GNOME Remote Desktop

Thu, 27 Aug 2026 13:02:40 +0300

tested on:

macOS version: Tahoe 26.3.1
Ubuntu version: 24.04 LTS

what we are going to do:

configure gnome-remote-desktop as a server on Ubuntu
install xfreerdp as a client on macOS
save login details to macOS keychain
create a shell function to connect to the server

notes:

only one GUI session can be open at a time. If you are connecting via RDP to the user and the user is already logged into a graphical interface locally on that machine, a new connection will be denied. You will have to close the existing GUI session and then connect again. read more

Ubuntu setup (server)

On Ubuntu, i.e. the machine you want to remotely access, you need to enable remote desktop sharing and create credentials

Connect to Ubuntu from macOS securely over Tailscale

Tue, 14 Apr 2026 21:24:10 +0300

Assumption: Both machines have tailscale already setup and logged in.

On Ubuntu, install SSH if it is not already

1sudo systemctl status ssh          # is sshd                                                    
2sudo apt install openssh-server    # install if missing                         
3sudo systemctl enable --now ssh                                                                 
4sudo ss -tlnp | grep :22           # confirm it's listening

Then from the client:

1tailscale status                   # confirm peer is online, get its tailscale IP/MagicDNS name 
2ssh user@<machine-name>            # or use the 100.x.y.z IP

UFW

Tailscale creates a new interface called tailscale0. It is better to allow incoming only on the tailscale0 interface instead of using a custom SSH port and opening it to the world. Any tailscale connection is encrypted by default

Stream Audio over WiFi from Linux Ubuntu PC to Android Phone

Wed, 20 Mar 2024 13:51:55 +0200

Why? Because i have more Android phones lying around than speakers.. I am using an Android phone as a wireless speaker for my PC

SoundWire by GeorgieLabs is an audio streaming system that lets you stream audio between devices be it Windows/macOS/Linux PCs or Android phones. You need to install the server on your PC from which you want to stream the audio, and the client in my case was the android app.

Troubleshooting UGREEN Bluetooth 5.4 adapter on Ubuntu Linux

Tue, 27 Feb 2024 19:28:56 +0200

NOTE: The dongle could not be used because of missing drivers and I was not able to install drivers for Linux.

Model No.: CM748 without antenna / CM749 with antenna
Chipset: Barrot BR8554
FCC ID: 2AQI5-CM748
Manufacturer ID: 33fa:0010

Status: no official drivers for Linux or macOS are available

Troubleshooting:

See if it is listed in connected USB devices lsusb
See if it is recognized as a Bluetooth device rfkill
See if there are kernel related errors dmesg

See if it is connected

nmap

Fri, 09 Feb 2024 16:35:02 +0200

find hacking targets
vulnerabilities that you can exploit
see what ports are open (default ports can tell you what services are running on these ports)

1# Scan entire network (ping an entire network to see what devices are online)
2nmap -sP 10.7.1.0
3
4nmap -v -A www.badstore.net
5
6sudo nmap -A 10.77.1.0/24

-v: verbose output
-A: Enable OS detection, version detection (for protocols), script scanning, and traceroute
-O: Enable OS detection

1sudo nmap -sT -p 80,443 10.7.1.0/24

sT TCP connect, i.e. full open scan

This scanning of entire networks might be blocked by firewalls (IDS: Intrusion Detection System) and may even be illegal. so you use -sS instead, the S is for stealthy

Installing Watchman on Ubuntu Linux

Wed, 20 Jul 2022 00:00:01 +0500

Install with Homebrew

1/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
2
3brew install watchman
4
5watchman --version

Install from official binary

 1VERSION='v2022.07.18.00'
 2# Check what the latest version is from: https://github.com/facebook/watchman/releases/latest
 3
 4wget https://github.com/facebook/watchman/archive/refs/tags/${VERSION}.zip
 5
 6unzip watchman-${VERSION}-linux.zip
 7cd watchman-${VERSION}-linux
 8
 9sudo mkdir -p /usr/local/{bin,lib} /usr/local/var/run/watchman
10sudo cp bin/* /usr/local/bin
11sudo cp lib/* /usr/local/lib
12sudo chmod 755 /usr/local/bin/watchman
13sudo chmod 2777 /usr/local/var/run/watchman
14
15watchman --version

Add Tor project repo to Ubuntu

Mon, 18 Jul 2022 23:39:34 +0500

NOTE: There is a bash script that takes care of everything in this article and more.

While most of you are familiar with Tor Browser, few are aware that it is a bundle that consists of two parts: the browser and the router. You can use the router to use commands like tor, torify and torsocks

Create a tor.list file inside /etc/apt/sources.list.d/

1sudo touch /etc/apt/sources.list.d/tor.list

Add official project source repos to the file

1# /etc/apt/sources.list.d/tor.list
2deb     [arch=$(dpkg --print-architecture) https://deb.torproject.org/torproject.org $(lsb_release -c | cut -f2) main
3deb-src [arch=$(dpkg --print-architecture) https://deb.torproject.org/torproject.org $(lsb_release -c | cut -f2) main

$(dpkg --print-architecture) will give you system architecture, e.g. amd64 (keep in mind that Ubuntu Focal dropped support for 32-bit)
$(lsb_release -c | cut -f2) will give you distribution codename, e.g. focal

Update sources and install the tor package

1apt update
2apt install apt-transport-https
3apt install tor

Update config

In /etc/tor/torrc, uncomment the lines #ControlPort 9051 and #CookieAuthentication 1 and change the CookieAuthentication value from 1 to 0

Install latest SML/NJ from source on Ubuntu (20.04)

Mon, 18 Jul 2022 12:58:45 +0500

Standard ML of New Jersey isn’t used much in modern day development but i needed to install it as part of my Programming Languages course.

The simplest way to install is sudo apt -y install smlnj, but it’ll install a slightly older version.

Here are all the steps on installing SML/NJ from source. You can save this as a script and run it with sudo bash foo.sh. sudo is needed if you want to create directories and download files under /usr/local

Add Tor browser on Ubuntu

Mon, 18 Jul 2022 00:00:00 +0500

There is a bash script that takes care of everything in this article and more.

Download the latest Tor browser package from the Tor downloads page, it’s signature and verify the package using signature and GPG key

 1# Download Tor browser package
 2wget https://www.torproject.org/dist/torbrowser/11.5/tor-browser-linux64-11.5_en-US.tar.xz
 3
 4# Download signature
 5wget https://www.torproject.org/dist/torbrowser/11.5/tor-browser-linux64-11.5_en-US.tar.xz.asc 
 6
 7# Import GPG key and Verify package with signature 
 8gpg --auto-key-locate nodefault,wkd --locate-keys torbrowser@torproject.org # import key
 9gpg --output ./tor-browser.keyring --export 0xEF6E286DDA85EA2A4BA7DE684E2C6E8793298290 # save key to file
10gpgv --keyring ./tor-browser.keyring tor-browser-linux64-11.5_en-US.tar.xz.asc  tor-browser-linux64-11.5_en-US.tar.xz # verify the signature of package using key

Extract and move to /opt for a system-wide install

1# Extract
2tar -xf tor-browser-linux64-11.5_en-US.tar.xz # gives a folder like: tor-browser_en-US
3sudo mv tor-browser_en-US /opt

Go to the install location and run the start-tor-browser.desktop and use --register-app so that it adds/updates the desktop shortcut

1sudo chmod +x /opt/tor-browser_en-US/start-tor-browser.desktop
2cd /opt/tor-browser_en-US
3./start-tor-browser.desktop --register-app

Install Standard ML of New Jersey (SML/NJ) on M1 Apple Silicon Macs (macOS Monterey)

Fri, 15 Jul 2022 15:12:12 +0500

1brew install smlnj
2
3echo 'export PATH=/usr/local/smlnj/bin:$PATH' >> ~/.zprofile

Even though the path for Homebrew on Apple Silicon macs has changed to /opt/homebrew, SML/NJ is installed under /usr/local/ instead. As a result, the recommended export PATH=$(brew --prefix)/smlnj/bin:"$PATH" on the cask documentation page does not work because brew --prefix will evaluate to /opt/homebrew

You also don’t need to pass the --cask it seems, no longer needed.

Test the install by running sml and you should get a REPL

Install multiple Java versions and switch between them

Thu, 17 Mar 2022 00:00:01 +0500

macOS

Download the tarball from here: https://jdk.java.net/16/

1sudo mv openjdk-16.0.1_osx-x64_bin.tar.gz /Library/Java/JavaVirtualMachines/
2cd /Library/Java/JavaVirtualMachines/
3sudo tar -xzf openjdk-16.0.1_osx-x64_bin.tar.gz
4sudo rm openjdk-16.0.1_osx-x64_bin.tar.gz

1echo -n "\nexport JAVA_HOME=`/usr/libexec/java_home -v16`" >> ~/.zprofile
2
3source ~/.zprofile

1java -version

/usr/libexec/java_home -v16 gives you the version specific path. If you wanted to use a different JDK version, say 17, then you’d update JAVA_HOME and set it to /usr/libexec/java_home -v17

Ubuntu Linux

1# java -version
2
3openjdk version "1.8.0_312"
4OpenJDK Runtime Environment (build 1.8.0_312-8u312-b07-0ubuntu1~20.04-b07)
5OpenJDK 64-Bit Server VM (build 25.312-b07, mixed mode)

1sudo apt install -y openjdk-17-jdk
2
3update-java-alternatives --list

java-1.11.0-openjdk-amd64      1111       /usr/lib/jvm/java-1.11.0-openjdk-amd64
java-1.17.0-openjdk-amd64      1711       /usr/lib/jvm/java-1.17.0-openjdk-amd64
java-1.8.0-openjdk-amd64       1081       /usr/lib/jvm/java-1.8.0-openjdk-amd64

1# sudo update-java-alternatives --set /path/to/java/version
2sudo update-java-alternatives --set /usr/lib/jvm/java-1.17.0-openjdk-amd64

Check version with java -version and you’ll see the new one

Install multiple Java versions and switch between them on macOS and Ubuntu

Thu, 17 Mar 2022 00:00:00 +0500

macOS

Simplest would be to installed with Homebrew:

1# /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
2📋
3brew install openjdk # installs openjdk@18

Alternatively, you can download the tarball from here: https://jdk.java.net/16/ and extract it to /Library/Java/JavaVirtualMachines/

1sudo mv openjdk-16.0.1_osx-x64_bin.tar.gz /Library/Java/JavaVirtualMachines/
2cd /Library/Java/JavaVirtualMachines/
3sudo tar -xzf openjdk-16.0.1_osx-x64_bin.tar.gz
4sudo rm openjdk-16.0.1_osx-x64_bin.tar.gz

Update $PATH

1echo -n "\nexport JAVA_HOME=`/usr/libexec/java_home -v16`" >> ~/.zprofile
2
3source ~/.zprofile

Confirm install

1java -version

openjdk version "16.0.1" 2021-04-20
OpenJDK Runtime Environment (build 16.0.1+9-24)
OpenJDK 64-Bit Server VM (build 16.0.1+9-24, mixed mode, sharing)

/usr/libexec/java_home -v16 gives you the version specific path. If you wanted to use a different JDK version, say 17, then you’d update JAVA_HOME and set it to /usr/libexec/java_home -v17

Disable Windows Defender permanently with Registry Editor

Wed, 23 Feb 2022 13:57:57 +0500

tl;dr Open regedit as Administrator and add a bunch of hexadecmial values here: Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender

Open regedit (Registry Editor) from the start menu. I did it as an Administrator just to make sure it works
Go here: Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender
Right click on Windows Defender and add the following as DWORD (32-bit) Value

Value Name	Value Data	Base
DisableBehaviorMonitoring	1	Hexadecimal
DisableOnAccessProtection	1	Hexadecimal
DisableScanOnRealtimeEnable	1	Hexadecimal

You may have to add a value and then double-click it again to set it’s data.

Automating the updating of GeoLocation database (GeoIP2 by MaxMind)

Wed, 04 Aug 2021 10:48:36 +0500

There are multiple ways of doing this.

Direct download script (with cron)

1GEOIPUPDATE_LICENSE_KEY=''
2
3#https://download.maxmind.com/app/geoip_download?edition_id=GeoLite2-Country&license_key=${GEOIPUPDATE_LICENSE_KEY}&suffix=tar.gz
4
5curl "https://download.maxmind.com/app/geoip_download?edition_id=GeoLite2-Country&license_key=${GEOIPUPDATE_LICENSE_KEY}&suffix=tar.gz" -o GeoLite2-Country.tar.gz \
6  && tar -xzvf GeoLite2-Country.tar.gz \
7  && mkdir -p /var/opt/maxmind/ \
8  && mv GeoLite2-Country_*/GeoLite2-Country.mmdb /var/opt/maxmind/GeoLite2-Country.mmdb

geoipupdate tool with cron

# top of crontab
MAILTO=your@email.com

38 2 * * 0,4 /usr/local/bin/geoipupdate
# end of crontab

As a Docker container using geoipupdate tool
As part of docker.compose.yml using official Docker container for geoipupdate

 1geoipupdate:
 2  container_name: geoip_update
 3  image: maxmindinc/geoipupdate
 4  restart: unless-stopped
 5  environment:
 6    GEOIPUPDATE_ACCOUNT_ID: ${GEOIPUPDATE_ACCOUNT_ID}
 7    GEOIPUPDATE_LICENSE_KEY: ${GEOIPUPDATE_LICENSE_KEY}
 8    GEOIPUPDATE_EDITION_IDS: GeoLite2-Country
 9    GEOIPUPDATE_FREQUENCY: 96 # number of hours between geoipupdate runs, 96 is four days, GeoIP2 Country is updated twice weekly on Tuesdays and Fridays
10  volumes:
11    - ./data/maxmind:/usr/local/share/GeoIP

This assumes you have a .env file in the project root that has your account ID and license key. Otherwise you can just hard code these values

Aliases in PowerShell

Tue, 06 Apr 2021 17:18:13 +0500

1# code $PROFILE.CurrentUserAllHosts
2code $PROFILE

1# Aliases for directories
2Function goToProjects { Set-Location -Path G:\Projects }
3
4Set-Alias -Name proj -Value goToProjects

The profile for the current user is at $PROFILE, but there are other ones for various hosts and all users as well
You can set aliases for commands, but you can not set aliases for commands that also take parameters. The workaround is to save the command with parameters as a function and then have an alias for that function instead of the command

Setting up an M1 MacBook Pro for Frontend Development

Wed, 24 Feb 2021 00:00:01 +0500

Install Xcode from the App Store and accept the default options. Install Xcode Command Line Developer Tools (don’t need Xcode installed first for that) xcode-select --install Install Homebrew

mkdir homebrew && curl -L https://github.com/Homebrew/brew/tarball/master | tar xz --strip 1 -C homebrew

brew install –cask visual-studio-code opera iterm2

Install Rosetta. WhatsApp prompted me and installed automatically, but you can manually install using the following command:

1softwareupdate --install-rosetta

DESIGN

Sketch
Photoshop
Illustrator
Figma

DEVELOP

Setting up an Orange Pi+ 2 for web development

Fri, 05 Feb 2021 21:13:48 +0500

As of September 2020 (version 1.50) VS Code is available for ARMv7 and ARM64. Orange Pi+ 2 is ARMV7
On the latest Armbian (Focal) for OrangePi Plus2, snap is already installed since it is based on Ubuntu 20.04.
You can NOT use snap to install VS Code, it’s available for amd64, but not armhf which OrangePi Plus2 is..
Node ``

VS Code

Download .deb file for ARM

Install with dpkg

1sudo dpkg -i ~/Downloads/code_1.53.0-1612367698_armhf.deb

It is very slow though. 2GB RAM on Armbian is obviously way too low to be running VS Code. I installed it just because i could. You’ll defintely notic the lag though. Geany is much faster, but Geany is not VS Code.

SSH into Windows from Linux

Fri, 05 Feb 2021 20:46:03 +0500

Set up SSH on Windows

Open PowerShell as Administrator and run the following command to see if OpenSSH is already installed

Get-WindowsCapability -Online | ? Name -like 'OpenSSH*'

Name  : OpenSSH.Client~~~~0.0.1.0
State : Installed

Name  : OpenSSH.Server~~~~0.0.1.0
State : Installed

In my case both client and server were installed but i still couldn’t connect, so i reinstalled it anyway and it worked afterwards..

# install the server and/or client features:
Add-WindowsCapability -Online -Name OpenSSH.Client~~~~0.0.1.0
Add-WindowsCapability -Online -Name OpenSSH.Server~~~~0.0.1.0

# start the ssh server daemon
Start-Service sshd

# This should return a Status of Running
Get-Service sshd

# add firewall rule to allow inbound and outbound traffic through port 22
New-NetFirewallRule -Name sshd -DisplayName 'OpenSSH Server (sshd)' -Service sshd -Enabled True -Direction Inbound -Protocol TCP -Action Allow -Profile Domain

# start automatically on Startup
Set-Service -Name sshd -StartupType 'Automatic'

Now you can SSH into the system like you normally would into any other system

Playing around with an Orange Pi+ 2

Fri, 05 Feb 2021 00:00:02 +0500

NOTES

The SATA interface is pretty useless without a special SATA split cable that i’ll have to order off of AliExpress
The SATA interface is also not a real SATA interface, more like a slow USB-to-SATA interface (SATA 2.0 - via GL830 USB-to-SATA bridge ref) like Banana Pi (which uses A20 SoC).
Needs an adaptor with enough juice to be able to power the HDD (specially if they are USB powered). I’m using a 5V 3A adaptor.
I’m using a 3.5" old school HDD (2TB) in a SATA casing and it comes with it’s own power adaptor and on/off switch.

TODO

Setup Git so i can write some code. Setup SSH keys for Github and Bitbucket
Setup NAS and share the files on Armbian over the network so that i can access easily files from other systems
Setup for running in headless mode (Enable SSH and remote connections, setup file sharing, automate torrent downloads etc.)
Catalogue the Orange Pi Plus 2 hardware details. (So that i don’t have to keep checking and so that i still have these details if/when the board gets forgotten online)
set up static IP

Installing and Upgrading Armbian

Installation had already been done the last time i set it up. This time i booted straight into the Armbian desktop. I can’t remember excatly why i chose Armbian over Debian/Ubuntu. Possibly because a reliable Ubuntu/Debian image for Orange Pi Plus 2 wasn’t available at that time, or maybe because Armbian is supposed to have better support for ARM based devices.

Orange Pi NAS

Fri, 05 Feb 2021 00:00:01 +0500

Connect hard drives over USB

Set up drives to auto-mount on system boot
Share the drives over the WiFi network

Setting up a NAS

Run the following commands before and after connecting your hard drive to figure out which one you need to mount.

1# get device UUIDs
2sudo blkid
3
4# find out partition names
5cat /proc/partitions

setting up for NTFS and EXT4 drives

1# install tools
2sudo apt-get install fuse ntfs-3g
3
4# create mount points
5sudo mkdir /media/aamnah/NAS /media/aamnah/STUFF
6
7# mount drive
8sudo mount -t ext4 /dev/sda1 /media/aamnah/NAS
9sudo mount -t ntfs-3g /dev/sdc1 /media/aamnah/STUFF

edit fstab to auto-mount drives

Orange Pi Plus 2 - System details

Fri, 05 Feb 2021 00:00:00 +0500

Processor / CPU info

1cat /proc/cpuinfo

Processor       : ARMv7 Processor rev 5 (v7l)
processor       : 0
BogoMIPS        : 1942.85

processor       : 1
BogoMIPS        : 1942.85

processor       : 2
BogoMIPS        : 1942.85

processor       : 3
BogoMIPS        : 1942.85

Features        : swp half thumb fastmult vfp edsp thumbee neon vfpv3 tls vfpv4 idiva idivt
CPU implementer : 0x41
CPU architecture: 7
CPU variant     : 0x0
CPU part        : 0xc07
CPU revision    : 5

Hardware        : sun8i
Revision        : 0000
Serial          : 94005035c618582a028e

1cat /proc/meminfo

MemTotal:        2062812 kB
MemFree:          650876 kB
Buffers:          103796 kB
Cached:           547892 kB
SwapCached:        42604 kB
Active:           517744 kB
Inactive:         651896 kB
Active(anon):     279676 kB
Inactive(anon):   353320 kB
Active(file):     238068 kB
Inactive(file):   298576 kB
Unevictable:          32 kB
Mlocked:              32 kB
HighTotal:       1318912 kB
HighFree:         201676 kB
LowTotal:         743900 kB
LowFree:          449200 kB
SwapTotal:        257848 kB
SwapFree:          41224 kB
Dirty:                 0 kB
Writeback:             0 kB
AnonPages:        475652 kB
Mapped:            77996 kB
Shmem:            115044 kB
Slab:              79480 kB
SReclaimable:      61952 kB
SUnreclaim:        17528 kB
KernelStack:        2760 kB
PageTables:         8776 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:     1289252 kB
Committed_AS:    3174836 kB
VmallocTotal:     245760 kB
VmallocUsed:       41056 kB
VmallocChunk:     196660 kB

1cat /proc/version

Linux version 3.4.113-sun8i (root@nightly) (gcc version 5.5.0 (Linaro GCC 5.5-2017.10) ) #68 SMP PREEMPT Wed Sep 19 10:23:30 CEST 2018

1uname # Operating System
2uname -a # Kernel version and System Architecture
3uname -m # Machine hardware name, tells whether system is 32-bit or 64-bit
4uname -p # Processor type (usually unknown on modern Unix)

1uname -a

Linux orangepiplus 3.4.113-sun8i #68 SMP PREEMPT Wed Sep 19 10:23:30 CEST 2018 armv7l armv7l armv7l GNU/Linux

i686 or i386 is 32-bit
x86_64 is 64-bit

OS

I’m running Armbian

Getting started with WebP on Ubuntu

Tue, 24 Nov 2020 00:00:00 +0500

1sudo apt update
2sudo apt install webp

1cwebp -q 100 sample_image.png -o sample_image.webp

1# convert all jpeg files in a folder
2for F in *.jpg; do cwebp $F -o `basename ${F%.jpg}`.webp; done
3
4# Convert all files in a directory
5for file in images/*; do cwebp "$file" -o "${file%.*}.webp"; done

using the `<picture>` tag

Before:

1<img src="flower.jpg" alt="" />

After:

1<!-- order of listing matters in source tag. top will be tried first -->
2<picture>
3  <source type="image/webp" srcset="flower.webp" />
4  <source type="image/jpeg" srcset="flower.jpg" />
5  <!-- img tag should always be included, and it should always be last -->
6  <img src="flower.jpg" alt="" />
7</picture>

key takeaways

i can automate the process of generating webp version whenever a new image file is uploaded
i can serve the images using mod_rewrite, and take care of it on a server level. No need to add <picture> elements inside existing code
going through the sample gallery, PNG files seem to look better after converted to WEBP
WebP offers both lossless and lossy compression. In lossless compression no data is lost. Lossy compression reduces file size, but at the expense of possibly reducing image quality.
you can use imagemin-webp as an npm package and integrate it into your bundler (Webpack, Grunt etc.)
In <picture>, the browser uses the first listed source that’s in a format it supports. If the browser does not support any of the formats listed in the <source> tags, it falls back to loading the image specified by the <img> tag.

Setting your Postfix self-hosted mail server up for multiple domains

Sat, 29 Aug 2020 13:04:42 +0500

With virtual alias domains, each hosted address is aliased to a local UNIX system account or to a remote address.
NEVER list a virtual alias domain name as a mydestination domain!
Execute the command postmap /etc/postfix/virtual after changing the virtual file, and execute the command postfix reload after changing the main.cf file.
Note: virtual aliases can resolve to a local address or to a remote address, or both. They don’t have to resolve to UNIX system accounts on your machine.

# /etc/postfix/main.cf
virtual_alias_domains = example.com ...other hosted domains...
virtual_alias_maps = hash:/etc/postfix/virtual

# /etc/postfix/virtual
postmaster@example.com postmaster
info@example.com       joe
sales@example.com      jane
# Uncomment entry below to implement a catch-all address
# @example.com         jim
...virtual aliases for more domains...

Mail accounts without system user accounts

Maildir style delivery where a mailbox pathname is used instead of a UNIX system account is used can be used to create virtual mailboxes. That way you don’t have to create a system account for every user that you want to give email accesss to.

Move Ubuntu `/home` partition to another one

Sun, 02 Aug 2020 10:38:12 +0500

Create a new partition in ext4 format
Trasnfer files from old partition to new partition
Switch over to new partition by editing /etc/fstab

If you’re trying to unmount the partition and it keeps saying it is busy, use the following command to see what’s keeping the partition busy

1lsof | grep/media/aamnah/Files

in my case it was a bunch of node processes..

Before starting file transfer, close all applications (e.g. Chrome) This will avoid any temporary files changing during the transfer.

Monitoring system resource usage and statistics on Ubuntu

Tue, 12 May 2020 00:00:01 +0500

Basically, i’m looking for answers to these:

Why did the server go down?
What process was taking so many resources that the server crashed?

CPU utilization history and logs with System Activity Reporter (SAR)

The sar command can give you CPU utilization history. It’s a part of a software bundle called sysstat which you’ll need to install on Debian/Ubuntu

 1# install
 2sudo apt install -y sysstat
 3
 4# enable data collection
 5# Set ENABLED="true" in "/etc/default/sysstat"
 6sudo sed -i 's/ENABLED="false"/ENABLED="true"/g' /etc/default/sysstat
 7
 8# change the collection interval from every 10 minutes to every 2 minutes.
 9sudo sed -i 's/5-55\/10/*\/2/g' /etc/cron.d/sysstat
10
11# restart sysstat for the change to take effect and data collection to start working
12sudo service sysstat restart
13
14
15# check cpu utilization
16sar

The logs are saved in /var/log/sa/

The ultimate guide to creating your own Zsh (oh-my-zsh) theme

Sat, 02 May 2020 00:00:00 +0500

Now that Zsh is now the default shell on macOS, i figured it was a good time to install oh-my-zsh and give it another go. And obviously, i immediately wanted to customize my prompt. So i ended up going through the process of creating a custom Zsh theme..

I need a minimalist prompt with

timestamp
git branch name and status
no username and hosts on local machine
a line break at the beginning of prompt to give visual separation between commands
no need for username and host. It’s my laptop, i know what my name and host is.

Something like this:

Change Swap partition in Ubuntu

Wed, 08 Apr 2020 00:00:00 +0500

Create swap and turn it on
add swap entry to fstab
update grub sudo gedit /etc/default/grub
update sudo gedit /etc/initramfs-tools/conf.d/resume
you can get UUID with sudo blkid
if you just update the fstab and not the RESUME values, it’ll not boot on the next restart, will give an error about resume device.

 1# prepare your partitions
 2swapoff /dev/sda2
 3mkswap /dev/sda3
 4swapon /dev/sda3
 5
 6# find swap uuid
 7sudo blkid | grep swap
 8# OR
 9sudo echo ls -l /dev/disk/by-uuid | grep sda3 |  cut -d' '  -f8 >> /etc/fstab
10
11# edit swap entry in /etc/fstab
12gksu gedit /etc/fstab
13
14# edit the uuid line in /etc/initramfs-tools/conf.d/resume
15gksu gedit /etc/initramfs-tools/conf.d/resume
16
17# In terminal, execute this command
18sudo update-initramfs -u

you can test your hibernation here, if it doesn’t work:

Setting up a WordPress Multisite Network in Subfolders

Wed, 25 Mar 2020 12:07:46 +0500

Enable multisite
Deactivate all installed plugins
Create network
Update config files

Keep in mind that creating sites in subdirectories doesn’t actually create any subdirectories on the file system, so you won’t see any new folders. It is all done within the database except maybe a folder under wp-content/uploads for Media files..

Enable multisite

Add the following to wp-config.php (before any require or include statements..)

1
2/**
3 * Allow WordPress Multisite network
4 */
5define( 'WP_ALLOW_MULTISITE', true );

Once you have it enabled, go back to Dashboard > Tools > Network Setup and confirm the settings. You’ll then be asked to edit the wp-config.php and .htaccess files again

Add CORS Header to an ASP.NET MVC project

Mon, 17 Feb 2020 06:36:03 +0500

Add the following to Web.config for the ASP.NET MVC app (inside the <configuration> block)

 1<!-- START: Add CORS header for WordPress site so we can dynamically fetch popular users there -->
 2<configuration>
 3  <system.webServer>
 4    <httpProtocol>
 5      <customHeaders>
 6        <add name="Access-Control-Allow-Origin" value="https://other.mydomain.net" />
 7      </customHeaders>
 8    </httpProtocol>
 9  </system.webServer>
10</configuration>
11<!-- END: Add CORS header for WordPress site so we can dynamically fetch popular users there -->

Make sure a <configuration>, <system.webServer>, <httpProtocol>, or <customHeaders> block doesn’t exist already. Better to search for these first and then add the code accordingly.

Enable CORS for WordPress API on Apache

Thu, 31 Oct 2019 18:25:20 +0500

Try 1. Edit `.htaccess`

1sudo a2enmod headers
2sudo service apache2 reload

.htaccess

<IfModule mod_headers.c>
  Header set Access-Control-Allow-Origin "*"
  Header set Access-Control-Allow-Methods: "POST, GET, OPTIONS, PUT, DELETE"
  Header set Access-Control-Allow-Credentials: true
  Header set Access-Control-Allow-Headers: X-Requested-With
</IfModule>

You can use add rather than set, but be aware that add can add the header multiple times, so it’s generally safer to use set.

https://www.w3.org/wiki/CORS_Enabled

Try 2. Edit `functions.php`

Put this in functions.php

 1// Enable CORS for the API
 2// https://gist.github.com/miya0001/d6508b9ba52df5aedc78fca186ff6088
 3// https://github.com/ahmadawais/WP-REST-Allow-All-CORS/blob/master/plugin.php
 4function my_customize_rest_cors() {
 5  remove_filter( 'rest_pre_serve_request', 'rest_send_cors_headers' );
 6  add_filter( 'rest_pre_serve_request', function( $value ) {
 7    header( 'Access-Control-Allow-Origin: *' );
 8    header( 'Access-Control-Allow-Methods: GET, POST, OPTIONS, PUT, DELETE' );
 9    header( 'Access-Control-Allow-Credentials: true' );
10    header( 'Access-Control-Expose-Headers: Link', false );
11    header( 'Access-Control-Allow-Headers: X-Requested-With' );
12    return $value;
13  } );
14}
15add_action( 'rest_api_init', 'my_customize_rest_cors', 15 );

Try 3. Edit Appache virtual host `.conf` file

Add the header inside the <Directory> section in the Apache virtual host files for the domain. (You may have 2 of them, one for SSL and one non-SSL)

Redirections with .htaccess file

Wed, 30 Oct 2019 00:00:00 +0500

Redirect the entire site (permanently)

1Redirect 301 / https://newsite.com

Redirect a single page

1Redirect 301 /oldpage.html https://newsite.com/newpage.html

You can specify any 3xx redirection code. Here is a list

Redirect an old domain to a new domain

1RewriteEngine On
2
3RewriteCond %{HTTP_HOST} ^mydomain.com [OR]
4RewriteCond %{HTTP_HOST} ^www.mydomain.com [OR]
5RewriteRule ^(.*)$ https://www.newdomain.com/$1 [L,R=301,NC]

If the requested page (condition) is not /wp-admin, /wp-login or wp-json, redirect it (rule) to the the new domain while keeping the path intact (because we are checking for REQUEST_URI)

Troubleshooting slow boot time on Ubuntu on an NVMe SSD

Sat, 27 Jul 2019 14:11:33 +0500

tl;dr: check if the swap drive has been changed or removed

Check the syslog

1tail -20 /var/log/syslog

Jul 27 13:46:06 PandaU systemd[1]: dev-disk-by\x2duuid-2854a8db\x2d6494\x2d41d0\x2d9cff\x2d974714bb0b00.device: Job dev-disk-by\x2duuid-2854a8db\x2d6494\x2d41d0\x2d9cff\x2d974714bb0b00.device/start timed out.
Jul 27 13:46:06 PandaU systemd[1]: Timed out waiting for device dev-disk-by\x2duuid-2854a8db\x2d6494\x2d41d0\x2d9cff\x2d974714bb0b00.device.
Jul 27 13:46:06 PandaU systemd[1]: Dependency failed for /dev/disk/by-uuid/2854a8db-6494-41d0-9cff-974714bb0b00.
Jul 27 13:46:06 PandaU systemd[1]: dev-disk-by\x2duuid-2854a8db\x2d6494\x2d41d0\x2d9cff\x2d974714bb0b00.swap: Job dev-disk-by\x2duuid-2854a8db\x2d6494\x2d41d0\x2d9cff\x2d974714bb0b00.swap/start failed with result 'dependency'.
Jul 27 13:46:06 PandaU systemd[1]: dev-disk-by\x2duuid-2854a8db\x2d6494\x2d41d0\x2d9cff\x2d974714bb0b00.device: Job dev-disk-by\x2duuid-2854a8db\x2d6494\x2d41d0\x2d9cff\x2d974714bb0b00.device/start failed with result 'timeout'.
Jul 27 13:48:37 PandaU dhclient[3143]: DHCPREQUEST of 192.168.0.79 on wlo1 to 192.168.0.1 port 67 (xid=0x52706f58)
Jul 27 13:48:37 PandaU dhclient[3143]: DHCPACK of 192.168.0.79 from 192.168.0.1
Jul 27 13:48:37 PandaU NetworkManager[1066]: <info>  [1564217317.7820] dhcp4 (wlo1):   address 192.168.0.79
Jul 27 13:48:37 PandaU NetworkManager[1066]: <info>  [1564217317.7820] dhcp4 (wlo1):   plen 24 (255.255.255.0)
Jul 27 13:48:37 PandaU NetworkManager[1066]: <info>  [1564217317.7820] dhcp4 (wlo1):   gateway 192.168.0.1
Jul 27 13:48:37 PandaU NetworkManager[1066]: <info>  [1564217317.7820] dhcp4 (wlo1):   lease time 600
Jul 27 13:48:37 PandaU NetworkManager[1066]: <info>  [1564217317.7820] dhcp4 (wlo1):   nameserver '192.168.0.1'
Jul 27 13:48:37 PandaU NetworkManager[1066]: <info>  [1564217317.7820] dhcp4 (wlo1): state changed bound -> bound
Jul 27 13:48:37 PandaU dbus-daemon[1056]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.nm-dispatcher.service' requested by ':1.14' (uid=0 pid=1066 comm="/usr/sbin/NetworkManager --no-daemon " label="unconfined")
Jul 27 13:48:37 PandaU systemd[1]: Starting Network Manager Script Dispatcher Service...
Jul 27 13:48:37 PandaU dbus-daemon[1056]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'
Jul 27 13:48:37 PandaU systemd[1]: Started Network Manager Script Dispatcher Service.
Jul 27 13:48:37 PandaU nm-dispatcher: req:1 'dhcp4-change' [wlo1]: new request (1 scripts)
Jul 27 13:48:37 PandaU nm-dispatcher: req:1 'dhcp4-change' [wlo1]: start running ordered scripts...
Jul 27 13:48:37 PandaU dhclient[3143]: bound to 192.168.0.79 -- renewal in 243 seconds.

Sure enough, the UUID it is trying to find (as it is listed in /etc/fstab) no longer exists. I ran blkid, got the new UUID of the swap partition and updated the /etc/fstab file.

Upgrade Gigabyte BIOS [H370M HD3 (rev. 1.0)]

Fri, 26 Jul 2019 00:00:01 +0500

Download the latest bios firmware
Extract the files to the root of a USB drive (FAT32 formatted)
Enter BIOS (F12)
Run the Q-Flash utility from BIOS (press the F8 button in BIOS). You can also access Q-Flash during post by pressing END
Take a backup of the existing BIOS.
Install the new one. It shows version numbers as file name, for example H370MHD3.F14 for the version released on 2019/07/08

Dual booting Windows and Linux

Fri, 26 Jul 2019 00:00:00 +0500

tl;dr: Life will be simpler if you just install Windows first and then Ubuntu later.

Unplug all other hard drives
Install Windows to SSD. With Windows installer create a partition for your Windows, it’ll create it’s Recovery and MSR (Microsoft Reserved Partition) partitions as well. Leave any extra space for your Ubuntu install later

The point of installing Windows first is so that it creates its Recovery and MSR partition and the partitioning scheme does not interfere with the BIOS and bootup. For example, if your drive is in MBR format, good luck figuring out disabling Safe Boot and Fast Boot, enabling CSM and Legacy Support, and wrangling with UEFI nonsense in general. Worst case scenario, your device wouldn’t even be recognized or listed by the motherboard. (actually happened!)

Configure WiFi from command line (Ubuntu 18.04)

Thu, 18 Jul 2019 10:40:01 +0500

tl;dr

1sudo su
2killall wpa_supplicant
3wpa_passphrase "your_essid" "your_password" >> /etc/wpa_supplicant/wpa_supplicant.conf
4wpa_supplicant -B -i wlp2s0  -c /etc/wpa_supplicant/wpa_supplicant.conf
5dhclient eth1

wpa_supplicant and dhclient require sudo

 1# figure out what's your WiFi interface called
 2iwlist scan
 3#iwconfig
 4
 5# scan for wifi networks
 6iwlist wlp2s0 scan
 7#iwlist wlp2s0 s
 8
 9
10# generate a 'network' entry for wpa_supplicant.conf file
11# replace MyWifiNetwork with the name of the wifi network you want to connect to
12# enter the wifi password when prompted
13sudo su
14wpa_passphrase MyWifiNetwork >> /etc/wpa_supplicant/wpa_supplicant.conf
15# you'll get a blinky cursor, enter the password now
16
17# connect to the network now
18wpa_supplicant -B -i wlp2s0  -c /etc/wpa_supplicant/wpa_supplicant.conf
19
20# obtain an IP address
21dhclient wlp2s0

NOTES:

Install Firefox Nightly on Ubuntu Linux 18.04

Wed, 10 Jul 2019 00:00:00 +0500

 1# Create /opt directory
 2sudo mkdir --mode=755 /opt
 3
 4# create a directory for firefox
 5sudo mkdir /opt/firefoxnightly
 6
 7# Download latest Nightly 64-Bit
 8wget -O firefoxnightly.tar.bz2 "https://download.mozilla.org/?product=firefox-nightly-latest-ssl&os=linux64&lang=en-US"
 9
10# Extract firefox to the folder we created for it in /opt
11tar xjf ~/Downloads/firefoxnightly.tar.bz2 /opt/firefoxnightly
12
13# give rights so that it auto-updates
14sudo chown -R $USER:$USER /opt/firefoxnightly
15
16# start Firefox Nightly 
17cd /opt/firefoxnightly && ./firefox

1. Download Firefox Nightly

You’ll get a .tar.bz2 file. Mozilla doesn’t provide .deb or .rpm packages since binaries are more universal and work on all distributions.

Install GoDaddy SSL Certificate on Apache

Fri, 26 Apr 2019 18:03:15 +0500

You need 4 files:

Certificate Signig Request (CSR), example.com.csr
Private Key, example.com.key
SSL Certificate, example.com.crt (GoDaddy: 7dbXXXXXXXXfef89.crt)
Intermediate Certificate, example.com.crt or intermediate.crt or chainfile.crt (GoDaddy: gd_bundle-g2-g1.crt)

1<VirtualHost 192.168.0.1:443>
2		DocumentRoot /var/www/html2
3		ServerName www.yourdomain.com
4		    SSLEngine on
5		    SSLCertificateFile /path/to/your_domain_name.crt
6		    SSLCertificateKeyFile /path/to/your_private.key
7		    SSLCertificateChainFile /path/to/DigiCertCA.crt
8</VirtualHost>

CSR

Generate a CSR (Certificate Signing Request) Key. Don’t add a passphrase, if you do it’ll ask you for the passphrase everytime you restart Apache.

1openssl req -newkey rsa:2048 -nodes -keyout example.com.key -out example.com.csr

-new used when creating a new CSR, rather than processing an existing one
-key the name of the file containing the key pair
-out name of the file to receive the CSR

You can use this CSR Decoder by GoDaddy to check your CSR

Fix slow boot after deleting Swap partition

Wed, 03 Apr 2019 16:48:08 +0500

tl;dr

Edit /etc/fstab. You need to comment out the lines that mount swap partitions. Ideally you should do this before deleing the swap partition
Edit /etc/initramfs-tools/conf.d/resume (with sudo) and comment out the swap partition
Edit /etc/crypttab if you had an encrypted swap partition
Edit /etc/default/grub if you had hibernation enabled for Ubuntu

You should update the /etc/fstab first, comment out the swap entries, and then delete the swap partition.

Editing /etc/fstab afterwards didn’t really fix the slow boot issue for me.

Troubleshooing a Mac

Fri, 15 Mar 2019 13:02:20 +0500

Issue: Computer is booting in Safe Mode (Shift Key) only

Do a Diagnostics Test (D) to check computer hardware

ref link

Shutdown. Power on and immediately press D. It’ll take a few minutes to run tests and give you results.
Mine gave me The battery requires service Reference Code: PPT004
It’ll also give you your Mac’s serial number. Mine is: C02KTD35F5V7

Check System Diagnostics Log file

See link 1, link 2, and link 3

Enabling pretty permalinks in Bitnami WordPress with SSL

Wed, 30 Jan 2019 18:08:21 +0500

tl;dr

Edit the /opt/bitnami/apache2/conf/extra/httpd-ssl.conf file and add the directives there. You need to wrap your .htaccess stuff in a <Directory> directive and that will be in turn inside the <VirtualHost> directive.

 1<VirtualHost _default_:443>
 2
 3#   General setup for the virtual host
 4DocumentRoot "/opt/bitnami/apps/wordpress/htdocs"
 5ServerName www.blah.com:443
 6ServerAdmin admin@blah.com
 7ErrorLog "/opt/bitnami/apache2/logs/error_log"
 8TransferLog "/opt/bitnami/apache2/logs/access_log"
 9
10<Directory "/opt/bitnami/apps/wordpress/htdocs">
11  AllowOverride All
12  Options FollowSymLinks
13
14  # BEGIN WordPress
15  RewriteEngine On
16  RewriteBase /
17  RewriteRule ^index\.php$ - [L]
18  RewriteCond %{REQUEST_FILENAME} !-f
19  RewriteCond %{REQUEST_FILENAME} !-d
20  RewriteRule . /index.php [L]
21  # END WordPress
22</Directory>
23
24</VirtualHost>

Restart Apache afterwards

Making sense of Bitnami Apache confs

Wed, 19 Dec 2018 00:00:00 +0500

Apache Conf

The main conf file for Apache is at /opt/bitnami/apache2/conf/httpd.conf

This file loads (sources) Bitnami specific conf files. Since these files are loaded at the end of the main Apache conf file, they’ll override the settings in the main conf.

/opt/bitnami/apache2/conf/httpd.conf in turn loads these two respectively at the end

1Include "/opt/bitnami/apache2/conf/bitnami/bitnami.conf"
2
3Include "/opt/bitnami/apache2/conf/bitnami/httpd.conf"

SSL Conf

There are 3 conf files that deal with Apache SSL inside the /opt/bitnami/apache2/conf folder

Create a 'New Document' shortcut in Nautlius File Manager

Wed, 12 Dec 2018 13:12:09 +0500

It’s fairly simple, just create a file in the ~/Templates folder, it’ll show up in the right click menu

1touch ${HOME}/Templates/Empty\ Document

The only caveat is that you have to rename the file after it’s created.

I used the name 1_Markdown.md for my file.

The .md extension because 90% of the files i create in Nautlius with the right click menu are Markdown files. I made other .sh, .js, .scss templates too..
1_ at the beginning means that it shows up at the top of the list view in the folder when it is set to sort A-Z

Mount NTFS drives in Linux

Mon, 10 Dec 2018 00:00:00 +0500

 1# install ntfs-3g
 2# on Ubuntu 18.04 ntfs-3g is already installed
 3sudo apt update && sudo apt install -y ntfs-3g
 4
 5# create a mount point for the drive ( /home/username/media/EXTRA )
 6mkdir -p ${HOME}/media/EXTRA
 7
 8# identify the NTFS drive
 9# sudo fdisk -l | grep NTFS
10# lsblk -f
11blkid
12
13# mount the drive ( /dev/sdb1 )
14sudo mount -t ntfs-3g /dev/sdb1 ${HOME}/media/EXTRA

Make it permanent by editing /etc/fstab. Keeping the mount point inside $HOME simplifies permissions

Setting up a frontend dev environment (Debian/Ubuntu)

Tue, 20 Nov 2018 00:00:00 +0500

tl;dr: TO DO: i have written a script here that will take care of the entire thing

Packages

1sudo apt update && sudo apt upgrade -y
2
3sudo apt install -y curl build-essential file git

build-essential includes gcc, g++ and make as well as other packages.

Node & Yarn

 1# install Node
 2# https://github.com/nodesource/distributions/blob/master/README.md
 3curl -sL https://deb.nodesource.com/setup_12.x | sudo -E bash -
 4sudo apt-get install -y nodejs
 5
 6# install Yarn
 7# curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
 8# echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
 9# sudo apt update && sudo apt install yarn
10
11# Install Yarn 2
12npm install -g yarn

If yarn global packages are not working, add Yarn to the $PATH.

1echo -e "
2
3## PATH - Yarn
4export PATH=$PATH:`yarn global bin`" >> ~/.bashrc

Homebrew

1# Homebrew
2# https://docs.brew.sh/Homebrew-on-Linux
3/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)"

Now confirm instal and update $PATH

Increasing performance on low-RAM

Fri, 26 Oct 2018 00:00:01 +0500

tl;dr

 1# Increase swappiness & cache pressure
 2sudo echo "
 3# increase swappiness
 4# https://help.ubuntu.com/community/SwapFaq
 5vm.swappiness=100
 6
 7# Cache Pressure Setting
 8# https://www.digitalocean.com/community/tutorials/how-to-add-swap-space-on-ubuntu-18-04
 9vm.vfs_cache_pressure=50" >> /etc/sysctl.conf
10
11# Create a new swap file and delete the old one
12sudo fallocate -l 8G /swapfile8G # create new file
13sudo chmod 600 /swapfile8G # recommended permissions
14sudo mkswap /swapfile8G # format file as swap
15sudo swapon /swapfile8G # turn it on
16sudo swapoff /swapfile # turn off old swapfile
17sudo sudo rm -rf /swapfile # remove old swap file
18sudo swapon -s # verify 
19
20# After all edit your /etc/fstab, if you use it to turn on swap when reboot, to switch /swapfile to /swapfile8G
21sudo nano /etc/fstab
22# /var/swapfile8G none swap sw 0 0

background:

I have an old Acer Aspire 5742 with 4GB of RAM that i’m trying to use for dev work. But the darn thing hangs up after running out of memory. The stuff i’m running is not much - VS Code, npm, Chromium with 6 or so tabs, Sublime Text for note taking and File explorer.

NTFS read/write on macOS

Mon, 07 May 2018 00:00:00 +0500

tl;dr

get Mounty!

1brew cask install mounty

If after copying the files are garyed out and are inaccessible, it’s because of Finder’s xattr file attributes.

1# list attributes
2ls -l@

1# delete Finder attributes
2xattr -d com.apple.FinderInfo FOO.ext

The old way

source This is more complicated than installing Mounty and didn’t work (the files didn’t show up in the Finder..)

 1# Install Command Line Tools
 2xcode-select --install
 3
 4# Install Homebrew
 5/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
 6
 7# Install ntfs-3g
 8brew install ntfs-3g
 9
10# create mount point
11sudo mkdir /Volumes/NTFS
12
13# determine your drive's partition
14diskutil list
15
16# unmount if partition was already mounted by Mac
17sudo umount /dev/disk2s1
18
19# mount the drive to the mount point you created
20sudo /usr/local/bin/ntfs-3g /dev/disk2s1 /Volumes/NTFS -olocal -oallow_other

First, download FUSE for macOS and install it. Use the default options when installing it.
Install Command Line Tools
Install Homebrew
Install ntfs-3g
Create mount point, /Volumes/NTFS in the example above
Determine your drive’s partition identifier, disk2s1 in the example above
Unmount partition if it was automatically mounted by your Mac
(Optional) Make an alias for the mount command e.g. mountntfs

Tranfer between Debian Apache based setups

Fri, 27 Apr 2018 00:00:01 +0500

Transfer server from DigitalOcean to Vultr

Transfering between Debian Apache based setups

This is my current setup

Apache, MySQL, PHP, phpMyAdmin on Ubuntu
Domains added via vhost conf files
Let’s Encrypt SSL certificates

Transfer databases
Transfer all vhost.conf files in /var/etc/site_enabled
Transfer all sites in /var/www
Transfer SSL certs for all domains

Transfer Domain Conf files

This involves

Locating where the conf files are
Copying them to new server

The conf files are usually in the /etc/apache2/sites-available folder and symlinked into the /etc/apache2/sites-enabled folder

Install sedutil on Ubuntu

Mon, 08 Jan 2018 00:00:00 +0500

 1# download sedutil
 2
 3# make sure requisite libs are installed 
 4sudo apt update && sudo apt upgrade -y
 5sudo apt install -y build-essential g++
 6
 7# install make tools
 8sudo apt install autoconf -y
 9
10# build sedutil (run from project root)
11autoreconf -i
12./configure
13make

Enable TPM libata.allow_tpm=1 by editing the GRUB config

1sudo nano /etc/default/grub

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash libata.allow_tpm=1"

sudo update-grub
reboot

Add sedutil-cli to $PATH so that it can be executed from anywhere in the shell

Configuring networking interfaces

Sun, 07 Jan 2018 00:00:00 +0500

Finding network interface

1# See a list of networks available
2ls /sys/class/net
3
4# See if your network is disabled
5sudo lshw -C network
6
7ip addr

Turn down a network

1sudo ip ls dev en0 down
2sudo ifdown en0

1# Enable interfaces
2sudo ifup -v eth0

The file to edit to configure networks

1sudo nano /etc/network/interfaces

Try booting in recovery and then enabling networking. This was the easiest way for me to get ethernet to work. From GRUB, select Advanced Options and boot in recovery mode.

Get all kinds of information about your Mac machine using the Terminal

Sat, 11 Nov 2017 00:00:01 +0500

1# generate a System Report..
2system_profiler

This command is the command line equivalent of going to About This Mac > System Report..

You might need this if you write Bash scripts for example where you want to know if a program is installed on the system or not.

If you just run the command in the Terminal, it will start outputting all kinds of information, LOADS of it, including stuff like your machine’s UUID, available Wi-Fi networks, system diagnostic tests, details about what Applications are installed on the system and their versions, the fonts installed, hardware overview and so on..

Resetting an 'Unavailable' Serial Number on a Mac

Sat, 11 Nov 2017 00:00:00 +0500

tl;dr

Note down your serial number (printed on underside of laptop, or purchase receipt)
Download and write Blank Board Serializer .dmg to a USB
Boot from USB by pressing the C key
Follow instructions and enter your serial number

Not having a serial number is usually due to a hardware change. Something was repaired, added (e.g. extra RAM) or replaced. The next common reason is software upgrade. Upgrading to OS X El Capitan has been reported to make the serial number go missing (the case with my 2013 Macbook Air, never repaired and bought directly from Apple in Dubai).

Use rsync to mirror websites

Wed, 06 Sep 2017 09:22:43 +0500

tl;dr

 1apt update && apt install rsync
 2
 3#Access via remote shell:
 4#  Pull: rsync [OPTION...] [USER@]HOST:SRC... [DEST]
 5#  Push: rsync [OPTION...] SRC... [USER@]HOST:DEST
 6
 7# Pull: sync remote with local
 8rsync -vhaze ssh user@server.example.com:/var/www/ /var/www
 9rsync -vPhaze "ssh -p 1234 -i /root/.ssh/id_rsa" root@server.example.com:/var/www/cakebox.me/public_html/ /var/www/cakebox.me/public_html
10rsync -qaze "ssh -p 1234 -i /root/.ssh/id_rsa" root@server.example.com:/etc/letsencrypt/archive :/etc/letsencrypt/live :/etc/letsencrypt/renewal /etc/letsencrypt/

-v, --verbose               increase verbosity
-h, --human-readable        output numbers in a human-readable format
-q, --quiet                 suppress non-error messages
-a, --archive               archive mode; equals -rlptgoD (no -H,-A,-X)
-z, --compress              compress file data during the transfer
-e, --rsh=COMMAND           specify the remote shell to use
    --progress              show progress during transfer
-P                          same as --partial --progress

explainshell for the rsync command.
-e is basically the shell to use, e.g. ssh -p 2234 -i /user/.ssh/id_rsa, followed by the command
-a is used for preservation (ownership, permissions, soft links etc.)
You can specify custom SSH port and SSH key to use for the connection. The path for the key file needs to be absolute path, ~ will not expand, so you have to use /userhome
Make sure which way you’re syncing. If note sure, you could end up overwriting imprtant files. For example config files with database connection details for example, this has happened.
An easy way to determine which way you are syncing is the -e flag. -e determines the remote shell, so if you’re using the option, you’re pulling, i.e. syncing remote changes to local.
-e can not be used when you’re syncing local changes to remote

Create an unprivileged user for the sake of transferring files

Taking care of prompt imputs from a script with Debconf

Sat, 12 Aug 2017 00:00:01 +0500

1sudo apt install debconf-utils -y

see what possible selections a package may have

1sudo debconf-get-selections | grep mysql

1mysql-server-5.7	mysql-server/root_password	password
2mysql-server-5.7	mysql-server/root_password_again	password
3mysql-server-5.7	mysql-server/no_upgrade_when_using_ndb	error
4mysql-server-5.7	mysql-server/password_mismatch	error
5mysql-server-5.7	mysql-server-5.7/start_on_boot	boolean	true
6mysql-server-5.7	mysql-server-5.7/postrm_remove_databases	boolean	false
7mysql-server-5.7	mysql-server-5.7/nis_warning	note
8mysql-server-5.7	mysql-server-5.7/really_downgrade	boolean	false

set those selections

1MYSQL_PASS='your_password'
2
3sudo debconf-set-selections <<< "mysql-server mysql-server/root_password password ${MYSQL_PASS}"
4sudo debconf-set-selections <<< "mysql-server mysql-server/root_password_again password ${MYSQL_PASS}"

Intro to debconf

Sat, 12 Aug 2017 00:00:00 +0500

tl;dr

debcnof is a configuration management tool
all the questions you get during installing .deb packages are stored in debconf
You can preload answers to those questions to get non-interactive/slient installations
needs sudo

 1sudo apt install debconf-utils
 2
 3# get configurable values for a package
 4sudo debconf-get-selections | grep mysql
 5
 6# set values 
 7echo "set mysql-server/root_password YOURPASSWORD" | debconf-communicate
 8# sudo debconf-set-selections <<< "mysql-server mysql-server/root_password password YOURPASSWORD"
 9# echo 'mysql-server mysql-server/root_password password YOURPASSWORD' | debconf-set-selections
10
11# show the list of debconf values configured for a package
12debconf-show phpmyadmin

debconf is a configuration management tool for Debain. It let’s you pre-load configurations, meaning you set configuration options before instaling a package. The major benefit of this is during scripting, you can pre-configure the values via debconf-set-selections and avoid entering values in the prompt, getting a non-interactive install.

Image Optimization on Linux Servers using jpegoptim and optipng

Fri, 11 Aug 2017 00:00:01 +0500

The idea is to have a script that runs periodically and compresses image files in specified directories

Optimize images in known directories, e.g. wp-content/uploads for WordPress, image/catalog/ in OpenCart etc.
Only optimize newly added files, instead of redoing the whole folder every time (on every cron run)
Setup a cron so it does it on it’s own, periodically (e.g. every day)

You being the developer might be conscious of optimizing images before you upload them, but the clients usually aren’t. In cases like these, you can optimize the images on the server after the client has uploaded them, without having to bother yourself or the client.

Intro to Rootkit Hunter

Fri, 11 Aug 2017 00:00:00 +0500

RKHunter downloads a list of known exploits and then checks your system against the database. It also alerts you if it detects unsafe settings in some common applications.

 1#!/bin/bash
 2
 3apt update && apt upgrade -y
 4
 5# Rootkit Hunter - Scan for Rootkits, backdoors and exploits
 6
 7EMAIL='' # email for sending logs
 8SERVER='' # server name
 9
10rkhunter() {
11	wget https://downloads.sourceforge.net/project/rkhunter/rkhunter/1.4.4/rkhunter-1.4.4.tar.gz
12	tar xf rkhunter-1.4.4.tar.gz
13	sudo rkhunter-1.4.4/installer.sh --install # by default it installs in /usr/local/bin (which is in $PATH)
14
15	# confirm install by checking version
16	sudo rkhunter --versioncheck
17
18	# Pre-run Updates
19	sudo rkhunter --update # update database
20	sudo rkhunter --propupd # Before running RKH, fill the file properties database (set baseline file properties so that rkhunter can alert us if any of the essential configuration files it tracks are altered)
21
22	# Scan
23	sudo rkhunter --check # scan the entire file system
24
25
26	# Cron
27	touch /etc/cron.daily/rkhunter.sh
28	echo -e "#!/bin/sh
29(
30/usr/local/bin/rkhunter --versioncheck
31/usr/local/bin/rkhunter --update
32/usr/local/bin/rkhunter --cronjob --report-warnings-only
33) | /bin/mail -s 'rkhunter Daily Run (${SERVER})' ${EMAIL}
34}" > /etc/cron.daily/rkhunter.sh
35	chmod 755 /etc/cron.daily/rkhunter.sh

SFTP Users for Website directory

Wed, 09 Aug 2017 00:00:00 +0500

tl;dr

The ChrootDirectory must be owned by root. You can enable access to dirs inside the ChrootDirectory owned by different users
The ChrootDirectory needs 755 permissions
Add everything to the END OF THE FILE. Or else it won’t work
Web directories /var/www need to be owned by www-data

What we’ll do

Create a Group for SFTP access
Add our users to that SFTP Group

Here’s what each of those directives do:

Install PHP5 on Ubuntu 17.04 Zesty Zapus

Thu, 06 Jul 2017 00:00:01 +0500

(Theoretically) You can install both PHP5 and PHP7 and switch between them.. If you only want PHP5, add the repo, install the packages for PHP 5.6 and end it there.

WARNING:

This leads to PhpMyAdmin not working if you install it afterwards..
Both versions working has not been tested in production.
If you check PHP version on system, php --version, it still shows PHP 7.0

add repo

There are no PHP 5.x packages in Zesty repositories. Only in the PPA, so you need to add the repo

Securing Wordpress

Wed, 05 Jul 2017 00:00:02 +0500

File Permissions

The default permission scheme should be:

Folders 755
Files 644

Avoid having any file or directory set to 777. 777 means global access. Usually only cache files have this permission.

Via command line you can run the following commands to change permissions recursively:

1# For Directories:
2find /path/to/your/wordpress/install/ -type d -exec chmod 755 {} \;
3
4# For Files:
5find /path/to/your/wordpress/install/ -type f -exec chmod 644 {} \;

Secured File Permissions for specific files

You should set these permissions

cPanel Web Templates and Skeleton Directory

Wed, 05 Jul 2017 00:00:00 +0500

Web Templates

/var/cpanel/webtemplates/user/english/

Web templates are default template .tmpl files that are shown for status pages.

Default Website Page (Has not yet been configured by the domain owner)
Account Move (Has moved)
Account Suspended (Has been suspended)
Connection Selection (Is experiencing a connection or firewall problem)

The files to edit are:

/var/cpanel/webtemplates/user/english/default.tmpl
/var/cpanel/webtemplates/root/english/moving.tmpl
/var/cpanel/webtemplates/root/english/redirect.tmpl
/var/cpanel/webtemplates/user/english/suspended.tmpl

Web Templates can also be edited via WHM > Account Functions > Web Template Editor

Skeleton Directory

/root/cpanel3-skel

This directory is what will be used as a skeleton for new accounts. For example if you place an index.html file in /root/cpanel3-skel/public_html, and then setup a new account, that account will have a copy of your index.html in their public_html directory.

Configure SFTP

Tue, 08 Mar 2016 00:00:00 +0500

The ChrootDirectory must be owned by root. You can enable access to dirs inside the ChrootDirectory owned by differet users
The ChrootDirectory needs 755 permissions
Add everything to the END OF THE FILE. Or else it won’t work
Web directories /var/www need to be owned by www-data

Setup link

Step 1 : Install OpenSSH package if not installed

1sudo apt-get install openssh-server

Step 2 : Create separate group for SFTP users.

Install ionCube Loader on Ubuntu 16.04

Sat, 13 Feb 2016 00:00:00 +0500

 1wget https://downloads.ioncube.com/loader_downloads/ioncube_loaders_lin_x86-64.tar.gz # download
 2tar xzvf ioncube_loaders_lin_x86-64.tar.gz # extract
 3php -v # find out PHP version e.g. 7.2
 4php -i | grep extension_dir # find out PHP extensions directory
 5
 6# copy closest matching ioncube module to your PHP extensions directory
 7sudo cp "ioncube/ioncube_loader_lin_7.0.so" /usr/lib/php/20160731/
 8
 9# copy this line to top of php.ini /etc/php/7.2/apache2/php.ini
10# OR copy this to a new configuration file `00-ioncube.ini` and load it (by moving to /etc/php/7.2/apache2/conf.d)
11# zend_etxension = path/to/module/file
12zend_extension = /usr/lib/php/20160731/ioncube_loader_lin_7.0.so

tl;dr

find out PHP version and extensions directory (7.2 and /usr/lib/php/20160731)
copy closest matching ionCube module to PHP extensions directory (ioncube/ioncube_loader_lin_7.0.so and /usr/lib/php/20160731)
copy one line of code to an .ini file and move it to additional .ini files directory (00-ioncube.ini, zend_extension = /usr/lib/php5/20121212/ioncube_loader_lin_7.0.so and /etc/php/7.2/apache2/conf.d)

ionCube Loader is a PHP Encoder used by companies like WHMCS to encode their software code. In order to use the software, you need to install ionCube.

System Administration on Aamnah - Frontend Web Developer

Connect from macOS to Ubuntu remote desktop using xfreerdp and GNOME Remote Desktop

Ubuntu setup (server)

Connect to Ubuntu from macOS securely over Tailscale

UFW

Stream Audio over WiFi from Linux Ubuntu PC to Android Phone

Troubleshooting UGREEN Bluetooth 5.4 adapter on Ubuntu Linux

nmap

Installing Watchman on Ubuntu Linux

Links

Add Tor project repo to Ubuntu

Install latest SML/NJ from source on Ubuntu (20.04)

Add Tor browser on Ubuntu

Links

Install Standard ML of New Jersey (SML/NJ) on M1 Apple Silicon Macs (macOS Monterey)

Install multiple Java versions and switch between them

macOS

Ubuntu Linux

Install multiple Java versions and switch between them on macOS and Ubuntu

macOS

Disable Windows Defender permanently with Registry Editor

Automating the updating of GeoLocation database (GeoIP2 by MaxMind)

Aliases in PowerShell

Links

Setting up an M1 MacBook Pro for Frontend Development

Setting up an Orange Pi+ 2 for web development

VS Code

SSH into Windows from Linux

Set up SSH on Windows

Playing around with an Orange Pi+ 2

NOTES

TODO

Installing and Upgrading Armbian

Orange Pi NAS

Setting up a NAS

setting up for NTFS and EXT4 drives

Orange Pi Plus 2 - System details

Processor / CPU info

OS

Getting started with WebP on Ubuntu

using the <picture> tag

key takeaways

Links

Setting your Postfix self-hosted mail server up for multiple domains

Mail accounts without system user accounts

Move Ubuntu `/home` partition to another one

Monitoring system resource usage and statistics on Ubuntu

CPU utilization history and logs with System Activity Reporter (SAR)

The ultimate guide to creating your own Zsh (oh-my-zsh) theme

Change Swap partition in Ubuntu

Setting up a WordPress Multisite Network in Subfolders

Enable multisite

Add CORS Header to an ASP.NET MVC project

Enable CORS for WordPress API on Apache

Try 1. Edit .htaccess

Try 2. Edit functions.php

Try 3. Edit Appache virtual host .conf file

Redirections with .htaccess file

Redirect an old domain to a new domain

Troubleshooting slow boot time on Ubuntu on an NVMe SSD

Upgrade Gigabyte BIOS [H370M HD3 (rev. 1.0)]

Dual booting Windows and Linux

Configure WiFi from command line (Ubuntu 18.04)

Install Firefox Nightly on Ubuntu Linux 18.04

1. Download Firefox Nightly

Install GoDaddy SSL Certificate on Apache

CSR

Fix slow boot after deleting Swap partition

Troubleshooing a Mac

Do a Diagnostics Test (D) to check computer hardware

Check System Diagnostics Log file

Enabling pretty permalinks in Bitnami WordPress with SSL

tl;dr

Making sense of Bitnami Apache confs

Apache Conf

SSL Conf

Create a 'New Document' shortcut in Nautlius File Manager

Mount NTFS drives in Linux

Setting up a frontend dev environment (Debian/Ubuntu)

Packages

using the `<picture>` tag

Try 1. Edit `.htaccess`

Try 2. Edit `functions.php`

Try 3. Edit Appache virtual host `.conf` file