In this tutorial, we will explore how to use sed (stream editor) with examples in the Markdown language. sed is a powerful command-line tool for text manipulation and is widely used for tasks such as search and replace, line filtering, and text transformations. What is described below barely scratches the surface what sed can do.

Table of Contents

1. Installing Sed
2. Basic Usage
3. Search and Replace
4. Deleting Lines
5. Inserting and Appending Text
6. Transformations
7. Working with Files
8. Conclusion

1. Installing Sed

Before we begin, make sure sed is installed on your system. It usually comes pre-installed on Unix-like systems (e.g., Linux, macOS). To check if sed is installed, open your terminal and run the following command:

sed --version

If sed is not installed, you can install it using your package manager. For example, on Ubuntu or Debian-based systems, you can use the following command:

sudo apt-get install sed

2. Basic Usage

To use sed, you need to provide it with a command and the input text to process. The basic syntax is as follows:

sed 'command' input.txt

Here, 'command' represents the action you want to perform on the input text. It can be a search pattern, a substitution, or a transformation. input.txt is the file containing the text to process. If you omit the file name, sed will read from the standard input.

3. Search and Replace

One of the most common tasks with sed is search and replace. To substitute a pattern with another in Markdown files, use the s command. The basic syntax is:

sed 's/pattern/replacement/' input.md

For example, to replace all occurrences of the word "apple" with "orange" in input.md, use the following command:

sed 's/apple/orange/' input.md

4. Deleting Lines

You can also delete specific lines from a Markdown file using sed. The d command is used to delete lines that match a particular pattern. The syntax is as follows:

sed '/pattern/d' input.md

For example, to delete all lines containing the word "banana" from input.md, use the following command:

sed '/banana/d' input.md

5. Inserting and Appending Text

sed allows you to insert or append text at specific locations in a Markdown file. The i command is used to insert text before a line, and the a command is used to append text after a line. The syntax is as follows:

sed '/pattern/i\inserted text' input.md
sed '/pattern/a\appended text' input.md

For example, to insert the line "This is a new paragraph." before the line containing the word "example" in input.md, use the following command:

sed '/example/i\This is a new paragraph.' input.md

6. Transformations

sed provides various transformation commands that can be used to modify Markdown files. Some useful commands include:

• y: Transliterate characters. For example, to convert all uppercase letters to lowercase, use:

  sed 'y/ABCDEFGHIJKLMNOPQRSTUVWXYZ/abcdefghijklmnopqrstuvwxyz/' input.md
  

• p: Print lines. By default, sed only prints the modified lines. To print all lines, use:

  sed -n 'p' input.md
  

• r: Read and insert the contents of a file. For example, to insert the contents of insert.md after the line containing the word "insertion point" in input.md, use:

  sed '/insertion point/r insert.md' input.md
  

These are just a few examples of the transformation commands available in sed.

7. Working with Files

By default, sed modifies the input in-place. To make changes to a file and save the output to a new file, you can use input/output redirection:

sed 'command' input.md > output.md

This command runs sed on input.md and saves the output to output.md. Be cautious when using redirection, as it will overwrite the contents of output.md if it already exists.

8. Conclusion

In this tutorial, we have explored the basics of using sed with Markdown files. You have learned how to perform search and replace operations, delete lines, insert and append text, apply transformations, and work with files. sed offers a wide range of capabilities, and with practice, you can become proficient in manipulating Markdown files using this powerful tool.

On August 1, 2023, the free tier for the Amazon Simple Email Service (SES) will change. We are adding more features to the SES free tier: it now includes more outbound email message sources, SES’ new Virtual Deliverability Manager, and a higher limit for receiving inbound messages. We are also lowering the free tier limit for outbound messages and reducing the duration of the SES free tier to 12 months.

This may affect your bill starting in August 2023. Since you are already using SES, you will be able to take advantage of the revised free tier for another 12 months (until August 2024). Based on your SES usage in May 2023, this change would not have affected your SES bill. Note this is an estimate based on your usage, and actual billing impact may vary depending on your usage patterns each month and any discounts you may have.

The revised SES free tier offers you more flexibility. Previously, the SES free tier included up 1,000 inbound email messages per month and up to 62,000 outbound messages per month when sent from AWS compute services such as Amazon EC2. The revised free tier includes up to 3,000 messages each month. You can receive inbound messages, send outbound messages sent from anywhere (not just AWS compute services), or try Virtual Deliverability Manager, which gives you easy access to detailed metrics to explore and monitor your email delivery and engagement rates. For new SES customers, the revised free tier is available for the 12 months after you start using SES; for existing SES customers, the revised free tier is available for 12 months starting August 1, 2023.

The revised SES free tier goes live on August 1, 2023, and your account(s) will be enrolled automatically. As part of this change, you will see the label you see on your SES bill for the pricing unit for inbound messages change from “Message” to “Count” - this matches the same way we label outbound messages. We are not able to offer an option to remain on the previous SES free tier model.

To learn more about SES' deliverability tools through Virtual Deliverability Manager, please see the documentation [1]. For more details about the previous free tier, visit the pricing page [2].

If you have any questions or concerns, please reach out to AWS Support [3].

[1] https://docs.aws.amazon.com/ses/latest/dg/vdm.html [2] https://aws.amazon.com/ses/pricing/ [3] https://aws.amazon.com/support

The bridge collapsed overnight near Columbus, Montana causing several train cars to be immersed in the Yellowstone River.

Portions of a freight train plunged into the Yellowstone River due to bridge collapse. (Image: AP)

A bridge that crosses the Yellowstone River in Montana collapsed early Saturday, plunging portions of a freight train carrying hazardous materials into the rushing water below.

The train cars were carrying hot asphalt and molten sulfur, Stillwater County Disaster and Emergency Services said. Officials shut down drinking water intakes downstream while they evaluated the danger after the 6 a.m. accident. An Associated Press reporter witnessed a yellow substance coming out of some of the tank cars.

David Stamey, the county’s chief of emergency services, said there was no immediate danger for the crews working at the site, and the hazardous material was being diluted by the swollen river. There were three asphalt cars and four sulfur cars in the river.

The train crew was safe and no injuries were reported, Montana Rail Link spokesman Andy Garland said in a statement. The asphalt and sulfur both solidify quickly when exposed to cooler temperatures, he said.

Railroad crews were at the scene in Stillwater County, near the town of Columbus, about 40 miles (about 64 kilometers) west of Billings. The area is in a sparsely populated section of the Yellowstone River Valley, surrounded by ranch and farmland. The river there flows away from Yellowstone National Park, which is about 110 miles (177 kilometers) southwest.

“We are committed to addressing any potential impacts to the area as a result of this incident and working to understand the reasons behind the accident,” Garland said.

The bridge collapse also took out a fiber-optic cable providing internet service to many customers in the state, the high-speed provider Global Net said. “This is the major fiber route ... through Montana,” a recording on the company’s phone line said Saturday. “This is affecting all Global Net customers. Connectivity will either be down or extremely slow.”

In neighboring Yellowstone County, officials said they instituted emergency measures at water treatment plants due to the “potential hazmat spill” and asked residents to conserve water.

The cause of the collapse is under investigation. The river was swollen with recent heavy rains, but it’s unclear whether that was a factor. The Yellowstone saw record flooding in 2022 that caused extensive damage to Yellowstone National Park and adjacent towns in Montana. Robert Bea, a retired engineering professor at the University of California Berkeley who has analyzed the causes of hundreds of major disasters, said repeated years of heavy river flows provided a clue to the possible cause.

“The high water flow translates to high forces acting directly on the pier and, importantly, on the river bottom,” Bea said. “You can have erosion or scour that removes support from the foundation. High forces translate to a high likelihood of a structural or foundation failure that could act as a trigger to initiate the accident.”

An old highway bridge that paralleled the railroad bridge — together, they were called the Twin Bridges — was removed in 2021 after the Montana Department of Transportation determined it was in imminent danger of falling. It wasn’t immediately clear when the railroad bridge was constructed or when it was last inspected. Bea said investigators would also want to look at whether there was wear or rust in bridge components as well as a record of maintenance, repair and inspections.

Federal Railroad Administration officials were at the scene working with local authorities. “As part of our investigation, we have requested and will thoroughly review a copy of recent bridge inspection reports from the owner for compliance with federal Bridge Safety Standards,” the agency said in a statement Saturday, noting that responsibility for inspections lies with bridge owners.

Kelly Hitchcock of the Columbus Water Users shut off the flow of river water into an irrigation ditch downstream from the collapsed bridge to prevent contents from the tank cars from reaching nearby farmland. The Stillwater County Sheriff’s Office called the group Saturday morning to warn it about the collapse, Hitchcock said.

The U.S. Environmental Protection Agency notes that sulfur is a common element used as a fertilizer as well as an insecticide, fungicide and rodenticide.

cross-posted from: https://lemmy.run/post/19113

In this tutorial, we will walk through the process of using the grep command to filter Nginx logs based on a given time range. grep is a powerful command-line tool for searching and filtering text patterns in files.

Step 1: Access the Nginx Log Files First, access the server or machine where Nginx is running. Locate the log files that you want to search. Typically, Nginx log files are located in the /var/log/nginx/ directory. The main log file is usually named access.log. You may have additional log files for different purposes, such as error logging.

Step 2: Understanding Nginx Log Format To effectively search through Nginx logs, it is essential to understand the log format. By default, Nginx uses the combined log format, which consists of several fields, including the timestamp. The timestamp format varies depending on your Nginx configuration but is usually in the following format: [day/month/year:hour:minute:second timezone].

Step 3: Determine the Time Range Decide on the time range you want to filter. You will need to provide the starting and ending timestamps in the log format mentioned earlier. For example, if you want to filter logs between June 24th, 2023, from 10:00 AM to 12:00 PM, the time range would be [24/Jun/2023:10:00:00 and [24/Jun/2023:12:00:00.

Step 4: Use Grep to Filter Logs With the log files and time range identified, you can now use grep to filter the logs. Open a terminal or SSH session to the server and execute the following command:

grep "\[24/Jun/2023:10:00:" /var/log/nginx/access.log | awk '$4 >= "[24/Jun/2023:10:00:" && $4 <= "[24/Jun/2023:12:00:"'

Replace starting_timestamp and ending_timestamp with the appropriate timestamps you determined in Step 3. The grep command searches for lines containing the starting timestamp in the log file specified (access.log in this example). The output is then piped (|) to awk, which filters the logs based on the time range.

Step 5: View Filtered Logs After executing the command, you should see the filtered logs that fall within the specified time range. The output will include the entire log lines matching the filter.

Additional Tips:

• If you have multiple log files, you can either specify them individually in the grep command or use a wildcard character (*) to match all files in the directory.
• You can redirect the filtered output to a file by appending > output.log at the end of the command. This will create a file named output.log containing the filtered logs.

That's it! You have successfully filtered Nginx logs using grep based on a given time range. Feel free to explore additional options and features of grep to further refine your log analysis.

cross-posted from: https://lemmy.run/post/19113

In this tutorial, we will walk through the process of using the grep command to filter Nginx logs based on a given time range. grep is a powerful command-line tool for searching and filtering text patterns in files.

Step 1: Access the Nginx Log Files First, access the server or machine where Nginx is running. Locate the log files that you want to search. Typically, Nginx log files are located in the /var/log/nginx/ directory. The main log file is usually named access.log. You may have additional log files for different purposes, such as error logging.

Step 2: Understanding Nginx Log Format To effectively search through Nginx logs, it is essential to understand the log format. By default, Nginx uses the combined log format, which consists of several fields, including the timestamp. The timestamp format varies depending on your Nginx configuration but is usually in the following format: [day/month/year:hour:minute:second timezone].

Step 3: Determine the Time Range Decide on the time range you want to filter. You will need to provide the starting and ending timestamps in the log format mentioned earlier. For example, if you want to filter logs between June 24th, 2023, from 10:00 AM to 12:00 PM, the time range would be [24/Jun/2023:10:00:00 and [24/Jun/2023:12:00:00.

Step 4: Use Grep to Filter Logs With the log files and time range identified, you can now use grep to filter the logs. Open a terminal or SSH session to the server and execute the following command:

grep "\[24/Jun/2023:10:00:" /var/log/nginx/access.log | awk '$4 >= "[24/Jun/2023:10:00:" && $4 <= "[24/Jun/2023:12:00:"'

Replace starting_timestamp and ending_timestamp with the appropriate timestamps you determined in Step 3. The grep command searches for lines containing the starting timestamp in the log file specified (access.log in this example). The output is then piped (|) to awk, which filters the logs based on the time range.

Step 5: View Filtered Logs After executing the command, you should see the filtered logs that fall within the specified time range. The output will include the entire log lines matching the filter.

Additional Tips:

• If you have multiple log files, you can either specify them individually in the grep command or use a wildcard character (*) to match all files in the directory.
• You can redirect the filtered output to a file by appending > output.log at the end of the command. This will create a file named output.log containing the filtered logs.

That's it! You have successfully filtered Nginx logs using grep based on a given time range. Feel free to explore additional options and features of grep to further refine your log analysis.

In this tutorial, we will walk through the process of using the grep command to filter Nginx logs based on a given time range. grep is a powerful command-line tool for searching and filtering text patterns in files.

Step 1: Access the Nginx Log Files First, access the server or machine where Nginx is running. Locate the log files that you want to search. Typically, Nginx log files are located in the /var/log/nginx/ directory. The main log file is usually named access.log. You may have additional log files for different purposes, such as error logging.

Step 2: Understanding Nginx Log Format To effectively search through Nginx logs, it is essential to understand the log format. By default, Nginx uses the combined log format, which consists of several fields, including the timestamp. The timestamp format varies depending on your Nginx configuration but is usually in the following format: [day/month/year:hour:minute:second timezone].

Step 3: Determine the Time Range Decide on the time range you want to filter. You will need to provide the starting and ending timestamps in the log format mentioned earlier. For example, if you want to filter logs between June 24th, 2023, from 10:00 AM to 12:00 PM, the time range would be [24/Jun/2023:10:00:00 and [24/Jun/2023:12:00:00.

Step 4: Use Grep to Filter Logs With the log files and time range identified, you can now use grep to filter the logs. Open a terminal or SSH session to the server and execute the following command:

grep "\[24/Jun/2023:10:00:" /var/log/nginx/access.log | awk '$4 >= "[24/Jun/2023:10:00:" && $4 <= "[24/Jun/2023:12:00:"'

Replace starting_timestamp and ending_timestamp with the appropriate timestamps you determined in Step 3. The grep command searches for lines containing the starting timestamp in the log file specified (access.log in this example). The output is then piped (|) to awk, which filters the logs based on the time range.

Step 5: View Filtered Logs After executing the command, you should see the filtered logs that fall within the specified time range. The output will include the entire log lines matching the filter.

Additional Tips:

• If you have multiple log files, you can either specify them individually in the grep command or use a wildcard character (*) to match all files in the directory.
• You can redirect the filtered output to a file by appending > output.log at the end of the command. This will create a file named output.log containing the filtered logs.

That's it! You have successfully filtered Nginx logs using grep based on a given time range. Feel free to explore additional options and features of grep to further refine your log analysis.

cross-posted from: https://lemmy.run/post/15922

Running Commands in Parallel in Linux

In Linux, you can execute multiple commands simultaneously by running them in parallel. This can help improve the overall execution time and efficiency of your tasks. In this tutorial, we will explore different methods to run commands in parallel in a Linux environment.

Method 1: Using & (ampersand) symbol

The simplest way to run commands in parallel is by appending the & symbol at the end of each command. Here's how you can do it:

command_1 & command_2 & command_3 &

This syntax allows each command to run in the background, enabling parallel execution. The shell will immediately return the command prompt, and the commands will execute concurrently.

For example, to compress three different files in parallel using the gzip command:

gzip file1.txt & gzip file2.txt & gzip file3.txt &

Method 2: Using xargs with -P option

The xargs command is useful for building and executing commands from standard input. By utilizing its -P option, you can specify the maximum number of commands to run in parallel. Here's an example:

echo -e "command_1\ncommand_2\ncommand_3" | xargs -P 3 -I {} sh -c "{}" &

In this example, we use the echo command to generate a list of commands separated by newline characters. This list is then piped (|) to xargs, which executes each command in parallel. The -P 3 option indicates that a maximum of three commands should run concurrently. Adjust the number according to your requirements.

For instance, to run three different wget commands in parallel to download files:

echo -e "wget http://example.com/file1.txt\nwget http://example.com/file2.txt\nwget http://example.com/file3.txt" | xargs -P 3 -I {} sh -c "{}" &

Method 3: Using GNU Parallel

GNU Parallel is a powerful tool specifically designed to run jobs in parallel. It provides extensive features and flexibility. To use GNU Parallel, follow these steps:

1. Install GNU Parallel if it's not already installed. You can typically find it in your Linux distribution's package manager.

2. Create a file (e.g., commands.txt) and add one command per line:

   command_1
   command_2
   command_3
   

3. Run the following command to execute the commands in parallel:

   parallel -j 3 < commands.txt
   

   The -j 3 option specifies the maximum number of parallel jobs to run. Adjust it according to your needs.

For example, if you have a file called urls.txt containing URLs and you want to download them in parallel using wget:

parallel -j 3 wget {} < urls.txt

GNU Parallel also offers numerous advanced options for complex parallel job management. Refer to its documentation for further information.

Conclusion

Running commands in parallel can significantly speed up your tasks by utilizing the available resources efficiently. In this tutorial, you've learned three methods for running commands in parallel in Linux:

1. Using the & symbol to run commands in the background.
2. Utilizing xargs with the -P option to define the maximum parallelism.
3. Using GNU Parallel for advanced parallel job management.

Choose the method that best suits your requirements and optimize your workflow by executing commands concurrently.

cross-posted from: https://lemmy.run/post/15922

Running Commands in Parallel in Linux

In Linux, you can execute multiple commands simultaneously by running them in parallel. This can help improve the overall execution time and efficiency of your tasks. In this tutorial, we will explore different methods to run commands in parallel in a Linux environment.

Method 1: Using & (ampersand) symbol

The simplest way to run commands in parallel is by appending the & symbol at the end of each command. Here's how you can do it:

command_1 & command_2 & command_3 &

This syntax allows each command to run in the background, enabling parallel execution. The shell will immediately return the command prompt, and the commands will execute concurrently.

For example, to compress three different files in parallel using the gzip command:

gzip file1.txt & gzip file2.txt & gzip file3.txt &

Method 2: Using xargs with -P option

The xargs command is useful for building and executing commands from standard input. By utilizing its -P option, you can specify the maximum number of commands to run in parallel. Here's an example:

echo -e "command_1\ncommand_2\ncommand_3" | xargs -P 3 -I {} sh -c "{}" &

In this example, we use the echo command to generate a list of commands separated by newline characters. This list is then piped (|) to xargs, which executes each command in parallel. The -P 3 option indicates that a maximum of three commands should run concurrently. Adjust the number according to your requirements.

For instance, to run three different wget commands in parallel to download files:

echo -e "wget http://example.com/file1.txt\nwget http://example.com/file2.txt\nwget http://example.com/file3.txt" | xargs -P 3 -I {} sh -c "{}" &

Method 3: Using GNU Parallel

GNU Parallel is a powerful tool specifically designed to run jobs in parallel. It provides extensive features and flexibility. To use GNU Parallel, follow these steps:

1. Install GNU Parallel if it's not already installed. You can typically find it in your Linux distribution's package manager.

2. Create a file (e.g., commands.txt) and add one command per line:

   command_1
   command_2
   command_3
   

3. Run the following command to execute the commands in parallel:

   parallel -j 3 < commands.txt
   

   The -j 3 option specifies the maximum number of parallel jobs to run. Adjust it according to your needs.

For example, if you have a file called urls.txt containing URLs and you want to download them in parallel using wget:

parallel -j 3 wget {} < urls.txt

GNU Parallel also offers numerous advanced options for complex parallel job management. Refer to its documentation for further information.

Conclusion

Running commands in parallel can significantly speed up your tasks by utilizing the available resources efficiently. In this tutorial, you've learned three methods for running commands in parallel in Linux:

1. Using the & symbol to run commands in the background.
2. Utilizing xargs with the -P option to define the maximum parallelism.
3. Using GNU Parallel for advanced parallel job management.

Choose the method that best suits your requirements and optimize your workflow by executing commands concurrently.

Running Commands in Parallel in Linux

In Linux, you can execute multiple commands simultaneously by running them in parallel. This can help improve the overall execution time and efficiency of your tasks. In this tutorial, we will explore different methods to run commands in parallel in a Linux environment.

Method 1: Using & (ampersand) symbol

The simplest way to run commands in parallel is by appending the & symbol at the end of each command. Here's how you can do it:

command_1 & command_2 & command_3 &

This syntax allows each command to run in the background, enabling parallel execution. The shell will immediately return the command prompt, and the commands will execute concurrently.

For example, to compress three different files in parallel using the gzip command:

gzip file1.txt & gzip file2.txt & gzip file3.txt &

Method 2: Using xargs with -P option

The xargs command is useful for building and executing commands from standard input. By utilizing its -P option, you can specify the maximum number of commands to run in parallel. Here's an example:

echo -e "command_1\ncommand_2\ncommand_3" | xargs -P 3 -I {} sh -c "{}" &

In this example, we use the echo command to generate a list of commands separated by newline characters. This list is then piped (|) to xargs, which executes each command in parallel. The -P 3 option indicates that a maximum of three commands should run concurrently. Adjust the number according to your requirements.

For instance, to run three different wget commands in parallel to download files:

echo -e "wget http://example.com/file1.txt\nwget http://example.com/file2.txt\nwget http://example.com/file3.txt" | xargs -P 3 -I {} sh -c "{}" &

Method 3: Using GNU Parallel

GNU Parallel is a powerful tool specifically designed to run jobs in parallel. It provides extensive features and flexibility. To use GNU Parallel, follow these steps:

1. Install GNU Parallel if it's not already installed. You can typically find it in your Linux distribution's package manager.

2. Create a file (e.g., commands.txt) and add one command per line:

   command_1
   command_2
   command_3
   

3. Run the following command to execute the commands in parallel:

   parallel -j 3 < commands.txt
   

   The -j 3 option specifies the maximum number of parallel jobs to run. Adjust it according to your needs.

For example, if you have a file called urls.txt containing URLs and you want to download them in parallel using wget:

parallel -j 3 wget {} < urls.txt

GNU Parallel also offers numerous advanced options for complex parallel job management. Refer to its documentation for further information.

Conclusion

Running commands in parallel can significantly speed up your tasks by utilizing the available resources efficiently. In this tutorial, you've learned three methods for running commands in parallel in Linux:

1. Using the & symbol to run commands in the background.
2. Utilizing xargs with the -P option to define the maximum parallelism.
3. Using GNU Parallel for advanced parallel job management.

Choose the method that best suits your requirements and optimize your workflow by executing commands concurrently.

As per reports, OceanGate's carbon fiber hull was unsuited for dives into such depths. In a video now going viral, CEO Stockton Rush is seen admitting that he knows there are issues, but he is taking the risk anyway.

OceanGate's sub Titan, (L), wreck of the Titanic on the seafloor (R)

The HMS Titanic had sunk on April 15, 1912, taking more than 1500 people with it. 111 years later, 4 high-profile passengers and the CEO of the OceanGate company, who was the pilot of the tourist submersible ‘Titan’, died after their sub imploded due to extreme pressure deep in the North Atlantic Ocean.

The US Coast Guard has confirmed that one of their ROVs from the vessel Horizon Arctic located the debris of a tail comb from the OceanGate sub-Titan approximately 1600 feet from the bow wreckage of the Titanic on the seafloor. Other debris was also found scattered in the general area. The debris was confirmed to be from Titan, the lost tourist sub from OceanGate.

Speaking to the media, OceanGate’s co-founder Guillermo Stohnlein said that in the case of any failure, the implosion would have been instantaneous.

It is notable here that the Titanic wreckage sits at a depth of around 3800 meters. As per reports, the implosion at a depth like that causes immediate crushing of the vessel and everything inside it. The pilot and the passengers would have died within a few milliseconds.

CEO of OceanGate was the pilot, the 4 passengers included the billionaire explorer Hamish Harding, a British-Pakistani father-son duo named Shahzada Dawood and Suleiman Dawood, and the popular ‘Mr Titanic’ Paul-Henry Nargeolet. Nargeolet, a French Navy veteran, was part of the first expedition to visit the wreck in 1987, just two years after it was found. He has earned the moniker ‘Mr. Titanic’ as he has reportedly spent more time at the wreck than any other explorer.

The deceased CEO’s wife is a descendant of an old couple who died in the Titanic disaster in 1912

Wendy Rush, the wife of OceanGate CEO Stockton Rush, is the great-great-grandaughter of Isidor and Ida Straus, an old couple who had perished in the Titanic disaster in 1912. The old couple was depicted in James Cameron’s Oscar-winning movie too.

Isidor and Ida Straus were first-class passengers who had refused to board a lifeboat and had gone down with the ship on that fateful night in 1912.

Titanic tours

Tourists spend thousands of dollars to be taken to the wreckage of the liner, 12,500ft underwater. It is claimed that OceanGate Expeditions charges $250,000 (£195,270) for a place on its eight-day expedition.

It is important to note that submersibles are different from submarines. A submersible needs a mother ship that can launch it and recover it. Contrary to it, a submarine has enough power to leave port and come back to port on its own.

37 years ago, the wreckage of the Titanic was discovered in the Atlantic, around 400 nautical miles from Newfoundland, Canada. A team led by legendary explorer Robert Ballard had found the vessel.

OceanGate sub had ‘quality’ issues

As per reports, OceanGate’s carbon fiber hull was unsuited for dives into such depths. In a video now going viral, CEO Stockton Rush is seen admitting that he knows there are issues, but he is taking the risk anyway.

On Sunday morning, the surface crew of the accompanying tug boat had lost contact with the submersible one hour and 45 minutes after it went down the sea.

OceanGate staff had confirmed that in addition to a very limited oxygen supply, those onboard will also be experiencing frigid temperatures.

As per reports, David Lochridge, former director of marine operations associated with OceanGate, had refused to greenlight the sub, citing that the viewport is only certified to withstand pressure up to the depth of 1300 meters. The wreckage of the Titanic sits at a depth of 3800 meters on the ocean floor.

Lochridge was fired by OceanGate later. Months later, over 3 dozen people from the industry, including deep sea explorers and oceanographers included, had voiced concerns and warned the company of potential ‘catastrophic problems’ with their tours using that sub. Lochridge had also stated that OceanGate was unwilling to have the sub inspected and certified by established agencies.

cross-posted from: https://lemmy.run/post/10868

Beginner's Guide to grep

grep is a powerful command-line tool used for searching and filtering text in files. It allows you to find specific patterns or strings within files, making it an invaluable tool for developers, sysadmins, and anyone working with text data. In this guide, we will cover the basics of using grep and provide you with some useful examples to get started.

Installation

grep is a standard utility on most Unix-like systems, including Linux and macOS. If you're using a Windows operating system, you can install it by using the Windows Subsystem for Linux (WSL) or through tools like Git Bash, Cygwin, or MinGW.

Basic Usage

The basic syntax of grep is as follows:

grep [options] pattern [file(s)]

• options: Optional flags that modify the behavior of grep.
• pattern: The pattern or regular expression to search for.
• file(s): Optional file(s) to search within. If not provided, grep will read from standard input.

Examples

Searching in a Single File

To search for a specific pattern in a single file, use the following command:

grep "pattern" file.txt

Replace "pattern" with the text you want to search for and file.txt with the name of the file you want to search in.

Searching in Multiple Files

If you want to search for a pattern across multiple files, use the following command:

grep "pattern" file1.txt file2.txt file3.txt

You can specify as many files as you want, separating them with spaces.

Ignoring Case

By default, grep is case-sensitive. To perform a case-insensitive search, use the -i option:

grep -i "pattern" file.txt

Displaying Line Numbers

To display line numbers along with the matching lines, use the -n option:

grep -n "pattern" file.txt

This can be helpful when you want to know the line numbers where matches occur.

Searching Recursively

To search for a pattern in all files within a directory and its subdirectories, use the -r option (recursive search):

grep -r "pattern" directory/

Replace directory/ with the path to the directory you want to search in.

Using Regular Expressions

grep supports regular expressions for more advanced pattern matching. Here's an example using a regular expression to search for email addresses:

grep -E "\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,}\b" file.txt

In this case, the -E option enables extended regular expressions.

Conclusion

grep is a versatile tool that can greatly enhance your text searching and filtering capabilities. With the knowledge you've gained in this beginner's guide, you can start using grep to quickly find and extract the information you need from text files. Experiment with different options and explore more advanced regular expressions to further expand your skills with grep. Happy grepping!

cross-posted from: https://lemmy.run/post/10868

Beginner's Guide to grep

grep is a powerful command-line tool used for searching and filtering text in files. It allows you to find specific patterns or strings within files, making it an invaluable tool for developers, sysadmins, and anyone working with text data. In this guide, we will cover the basics of using grep and provide you with some useful examples to get started.

Installation

grep is a standard utility on most Unix-like systems, including Linux and macOS. If you're using a Windows operating system, you can install it by using the Windows Subsystem for Linux (WSL) or through tools like Git Bash, Cygwin, or MinGW.

Basic Usage

The basic syntax of grep is as follows:

grep [options] pattern [file(s)]

• options: Optional flags that modify the behavior of grep.
• pattern: The pattern or regular expression to search for.
• file(s): Optional file(s) to search within. If not provided, grep will read from standard input.

Examples

Searching in a Single File

To search for a specific pattern in a single file, use the following command:

grep "pattern" file.txt

Replace "pattern" with the text you want to search for and file.txt with the name of the file you want to search in.

Searching in Multiple Files

If you want to search for a pattern across multiple files, use the following command:

grep "pattern" file1.txt file2.txt file3.txt

You can specify as many files as you want, separating them with spaces.

Ignoring Case

By default, grep is case-sensitive. To perform a case-insensitive search, use the -i option:

grep -i "pattern" file.txt

Displaying Line Numbers

To display line numbers along with the matching lines, use the -n option:

grep -n "pattern" file.txt

This can be helpful when you want to know the line numbers where matches occur.

Searching Recursively

To search for a pattern in all files within a directory and its subdirectories, use the -r option (recursive search):

grep -r "pattern" directory/

Replace directory/ with the path to the directory you want to search in.

Using Regular Expressions

grep supports regular expressions for more advanced pattern matching. Here's an example using a regular expression to search for email addresses:

grep -E "\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,}\b" file.txt

In this case, the -E option enables extended regular expressions.

Conclusion

grep is a versatile tool that can greatly enhance your text searching and filtering capabilities. With the knowledge you've gained in this beginner's guide, you can start using grep to quickly find and extract the information you need from text files. Experiment with different options and explore more advanced regular expressions to further expand your skills with grep. Happy grepping!