Bash

bash script to remove the word ‘DALL·E’ from all filenames

 in Bash / GNU/Linux  tagged bash / rename by

To remove the word “DALL-E” from all filenames in a directory, you can use a bash script with rename (or mmv if rename isn’t available on your system). Here is a simple bash script to achieve this:

# Iterate over all files in the current directory
for file in *DALL·E*; do
  # Remove 'DALL·E' from the filename
  new_file=$(echo "$file" | sed 's/DALL·E//g')
  # Rename the file
  mv "$file" "$new_file"
done

echo "Renaming completed."

Explanation:

  1. for file in *DALL·E*; do: This loop iterates over all files in the current directory that contain the word “DALL·E”.
  2. new_file=$(echo "$file" | sed 's/DALL-E//g'): This line uses sed to remove the word “DALL·E” from the filename. The s/DALL-E//g pattern tells sed to replace “DALL·E” with nothing, effectively removing it.
  3. mv "$file" "$new_file": This renames the original file to the new filename.
  4. done: This marks the end of the loop.
  5. echo "Renaming completed.": This prints a message indicating that the renaming process is complete.

Usage:

  1. Save the script to a file, for example, rename_files.sh.
  2. Make the script executable:
   chmod +x rename_files.sh
  1. Run the script in the directory where you want to rename the files:
   ./rename_files.sh

This will rename all files in the current directory by removing the word “DALL·E” from their filenames.

Converting WebP Images to PNG Using parallel and dwebp

 in Bash / GNU/Linux  tagged convert / dwebp / parallel / png / webp by

In this post, we’ll walk through how to efficiently convert multiple WebP images to PNG format using the parallel and dwebp tools. This method is particularly useful when dealing with a large batch of images, as it leverages parallel processing to speed up the conversion.

Step 1: Install Necessary Tools

First, we need to install the webp and parallel packages. These can be installed on a Debian-based system (like Ubuntu) using the following command:

sudo apt install webp parallel
  • webp is a package that includes the dwebp tool, which is used for decoding WebP images.
  • parallel is a shell tool for executing jobs in parallel, making the conversion process faster.

Step 2: Convert WebP Images to PNG

Once the tools are installed, you can use the following command to convert all .webp files in the current directory to .png files:

parallel dwebp {} -o {.}.png ::: *.webp

Let’s break down this command:

  1. parallel: This is the GNU parallel command. It allows you to run shell commands in parallel.
  2. dwebp: This is the command-line tool to decode WebP files to other formats, like PNG.
  3. {}: This placeholder represents each input file passed to parallel.
  4. -o {.}.png: This specifies the output format. {.} removes the file extension from the input file, and .png appends the new file extension. For example, image.webp will be converted to image.png.
  5. :::: This indicates the start of the input list for parallel.
  6. *.webp: This is a wildcard pattern that matches all .webp files in the current directory.

Example

Assume you have three WebP files in your directory: image1.webp, image2.webp, and image3.webp. Running the command will convert these files to image1.png, image2.png, and image3.png respectively.

Benefits of Using parallel

  • Speed: By leveraging multiple CPU cores, parallel significantly reduces the time needed for batch processing.
  • Simplicity: Using a single command to handle all files in a directory is straightforward and minimizes the risk of manual errors.

With these steps, you can efficiently convert a large number of WebP images to PNG format, saving time and computational resources.

Deep Dive into Wget: Mirroring Websites for Offline Access

 in Bash / GNU/Linux  tagged archive / mirror / static / Website / wget by

In the realm of command-line utilities, wget stands out as a versatile tool for downloading files and websites from the internet. Whether you’re a developer, a researcher, or just someone looking to have offline access to web resources, understanding how to use effectively wget can greatly enhance your workflow. Today, we’re exploring a potent combination of flags: -mpEk, applied to mirroring the European Cyber Security Challenge (ECSC) website.

Understanding Wget

wget is a non-interactive network downloader that allows you to download web files. It supports HTTP, HTTPS, and FTP protocols and retrieval through HTTP proxies. It’s designed to be robust in handling transient network issues and can resume interrupted downloads, making it a reliable tool for comprehensive tasks like mirroring entire websites.

Breaking Down the Command: wget -mpEk https://challenges.ecsc.eu/

Let’s dissect the command wget -mpEk https://challenges.ecsc.eu/ to understand the role of each option:

  • -m (--mirror): This option turns on options suitable for mirroring websites, which includes infinite recursion depth, timestamping, and keeping the server’s directory listing, among other settings. It’s designed to make a replica of the site for offline viewing.
  • -p (--page-requisites): This tells wget to download all the files that are necessary to properly display a given HTML page. This includes such things as in-page images, stylesheets, and scripts.
  • -E (--adjust-extension): When saving files, wget will automatically adjust the extensions of HTML/HTML-like files (.html or .htm) to .html if they don’t already have one. This ensures that locally saved web pages are easily identifiable and accessible.
  • -k (--convert-links): After the download is complete, this option converts the links in the downloaded website, making them suitable for offline viewing. It adjusts links to images, stylesheets, and other web page components to point to local files.
  • https://challenges.ecsc.eu/: This is the URL of the website you want to mirror. In this example, it’s the homepage of the European Cyber Security Challenge, a notable event in the cybersecurity field.

Practical Applications

Why would someone want to use wget with these specific options? Here are a few scenarios:

  • Offline Viewing: For individuals who want to access the ECSC challenge website without an internet connection, perhaps for educational purposes or to ensure they have access to the content during travel.
  • Web Development: Developers might mirror a website to test website migration, analyze the structure of a website, or archive content before a major update.
  • Research and Archiving: Researchers or archivists may use wget to preserve digital content that’s at risk of being updated or removed.

Conclusion

The wget -mpEk https://challenges.ecsc.eu/ command showcases the power of wget for downloading and mirroring web content for offline use. By understanding and utilizing these options, users can efficiently archive entire websites, ensuring content is accessible regardless of their internet connectivity. Whether for professional use, educational purposes, or personal archiving, mastering wget commands like these opens up a world of possibilities for accessing and preserving online content.

This blog post aims to provide a comprehensive overview of the wget -mpEk command, making it accessible and understandable for readers who might not be familiar with command-line tools or the specific nuances of website mirroring.

Executing a Cron Job Within an Anaconda Environment

 in Bash / GNU/Linux  tagged anaconda / conda / cron / crontab by

For those seeking to automate their Python scripts using cron jobs within an Anaconda environment, there’s a straightforward method to ensure your scripts run under the correct environment. This approach involves leveraging the capabilities of bash and the configuration of your cron environment to recognize and activate the necessary Anaconda environment. Here’s how to set it up:

  1. Export Anaconda Initialization to a Dedicated Configuration File First, isolate the Anaconda initialization snippet from your ~/.bashrc file by copying it to a new file, say ~/.bashrc_for_cron. This step ensures the cron environment can source the necessary configurations to activate Anaconda environments. Make sure that:
  • The file is readable by the user scheduling the cron job.
  • The file is secured against write access from other users to mitigate security risks.
  1. Configure Cron to Use Bash and Source the Anaconda Configuration Edit your crontab configuration by running crontab -e and prepend your cron jobs with two crucial lines:
   SHELL=/bin/bash
   BASH_ENV=~/.bashrc_for_cron

These lines configure cron to execute jobs using bash instead of the default sh shell and to source the Anaconda configurations from ~/.bashrc_for_cron. When invoked by cron, this setup ensures that bash is aware of the necessary environment to activate Anaconda environments.

  1. Activate Anaconda Environment Before Executing Your Script When scheduling your Python script in crontab -e, prefix the command with the conda activate instruction to switch to your desired Anaconda environment. For instance, to run a script at 12:30 AM every day within a specific Anaconda environment, your cron job entry would look like:
   30 0 * * * conda activate opencv_env; python /path/to/script.py

This ensures that the script executes within the context of the specified Anaconda environment, opencv_env, leveraging any dependencies or configurations defined within that environment.

By following these steps, you can seamlessly schedule and run Python scripts under specific Anaconda environments, leveraging cron’s scheduling capabilities while ensuring the correct environment and dependencies for your scripts.