Embedded Files
Here is some Linux help for my reference. This might be useful for some of you as well.
- Setup a virtual audio device
You need to have pulseaudio and pavucontrol installed in your system.
Create a virtual output device (virtual sink) named vspeaker
pactl load-module module-null-sink sink_name=vspeaker sink_properties=device.description=virtual_speaker
Create a virtual input source (monitor) based on the virtual sink
pactl load-module module-remap-source master=vspeaker.monitor source_name=vmic source_properties=device.description=virtual_mic
2. Conda, a package and environment management system
2. Conda, a package and environment management system
To know conda version
conda info
To list the conda environment
conda list env
To list the installed packages in an environment
conda list
To create a new environment named phy24
conda create --name phy24 python=3.12
To activate/deactivate the environment phy24
source activate phy24
source deactivate
To show all the added channels
conda config --show channels
To install a package pytorch from a particular channel pytorch
conda install -c pytorch pytorch
To add a particular channel pytorch
conda config -add channels pytorch
3. Embed interactive SageMath cells in a webpage
3. Embed interactive SageMath cells in a webpage
<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width">
<title>SageMathCell</title>
<script src="https://sagecell.sagemath.org/static/embedded_sagecell.js"></script>
<script>
// Make the div with class 'compute' a Sage cell
sagecell.makeSagecell({
inputLocation: 'div.compute',
evalButtonText: 'Evaluate'
});
</script>
</head>
<body>
<h2>Computations examples</h2>
<h3>Plot the sin(x) function.</h3>
<div class="compute">
<script type="text/x-sage">
# Define the range
start = 0
end = 2 * pi
# Create the plot
plot(sin(x), (x, start, end), title='Plot of sin(x)', legend_label='sin(x)', gridlines=True)
</script>
</div>
</body>
</html>
4. at commands summary
4. at commands summary
Time and data formats for at command: now/midnight/noon/teatime; 10:37am/00:30 ; today/tomorrow/Friday/weekend ; +3 minutes/hours/days/weeks ; Aug 16 2024/16.08.24/081624/08162024
To schedule a job using the command prompt
at 3:05pm Monday
To schedule a job using pipe
echo "tar -xf /home/uttam/file.tar.gz" | at 4pm 16.08.2023
To schedule jobs in a bash script file
at midnight +30 minutes -f /home/uttam/file.sh
To display the list of scheduled jobs
atq
at -l
To remove a scheduled job
atrm [job number]
at -r [job number]
To display the content of scheduled jobs
at -c [job number]
5. Bash script to make downloads from given urls
5. Bash script to make downloads from given urls
#!/bin/bash
# Check if the user provided a filename
if [ "$#" -ne 1 ]; then
echo "Usage: $0 <urls_file>"
exit 1
fi
# Get the filename from the first argument
urls_file=$1
# Check if the file exists
if [ ! -f "$urls_file" ]; then
echo "File $urls_file does not exist."
exit 1
fi
# Create a temporary file to save the output
tmpfile=$(mktemp /tmp/download_output.XXXXXX)
# Download the files and save the output to the temporary file
{
wget -c --tries=5 -i "$urls_file"
echo "Download completed."
} &> "$tmpfile"
# Inform the user where the output has been saved
echo "The output has been saved to $tmpfile"
6. A sample .desktop file
6. A sample .desktop file
[Desktop Entry]
Name=PulseAudio Volume Control
GenericName=Volume Control
Comment=Adjust the volume level
Exec=/command/line/with/full/path
Type=Application
Path=/set/current/dir
Icon=/path/to/image/file
Terminal=false
Keywords=pavucontrol;Audio;Mixer;Output;Input;Devices
MimeType=
Put the desktop file in ~/.local/share/applications for a particular user or in /usr/share/applications for all users.
7. Compiz, an X window manager
7. Compiz, an X window manager
To install compiz and compiz-plugins packages in Ubuntu
sudo apt install compizconfig-settings-manager compiz-plugins
To customize window size and placement for a particular application, use the Place Windows and Window Rules plugins in the Window Management section of compizconfig-settings-manager.
8. LaTeX formulas in html code using KaTeX
8. LaTeX formulas in html code using KaTeX
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>KaTeX Example</title>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/katex@0.16.3/dist/katex.min.css">
<script defer src="https://cdn.jsdelivr.net/npm/katex@0.16.3/dist/katex.min.js"></script>
<script defer src="https://cdn.jsdelivr.net/npm/katex@0.16.3/dist/contrib/auto-render.min.js" onload="renderMathInElement(document.body);"></script>
</head>
<body>
<p>Wave functions of a one-dimensional infinite square well: <span class="katex">$$\psi_n(x) = \sqrt{\frac{2}{L}}\sin\left(\frac{n\pi x}{L}\right)$$</span></p>
</body>
</html>
9. Adjust the brighness of external monitor using ddcutil
9. Adjust the brighness of external monitor using ddcutil
Check your monitor supports DDC/CI (Display Data Channel Command Interface)
ddcutil detect
Get Current Brightness Value
ddcutil getvcp 10
Set Brightness Value
sudo ddcutil setvcp 10 <value>
10. Markdown cheat sheet
10. Markdown cheat sheet
11. Remove password from an encrypted PDF file
11. Remove password from an encrypted PDF file
Using QPDF tool
qpdf --password=<password> --decrypt <input_file.pdf> <output_file.pdf>
Using Ghostscript
gs -dNOPAUSE -dBATCH -q -sDEVICE=pdfwrite -sPDFPassword=<password> -sOutputFile=<output_file.pdf> -f <input_file.pdf>
12. Information about a connected Hard Disk
12. Information about a connected Hard Disk
Using lsblk
lsblk
Using fdisk
sudo fdisk -l
Using parted
sudo parted -l
Using lsusb or lspci
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