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How to Modify Specific Values in CSV Files Using AWK

Learn how to use the `awk` command to change specific column and row values in CSV files with clear, step-by-step instructions. --- This video is based on the question https://stackoverflow.com/q/75985963/ asked by the user 'Dibyajyoti Giri' ( https://stackoverflow.com/u/19878468/ ) and on the answer https://stackoverflow.com/a/75985987/ provided by the user 'Discussian' ( https://stackoverflow.com/u/14548240/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions. Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: change an item at specific column and row using awk Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l... The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license. If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com. --- Changing Values in CSV Files with AWK When working with CSV files, there may be times when you need to modify specific values at the intersection of particular rows and columns. If you are familiar with the awk command, you can easily perform this task. In this guide, we'll explore how to change a value in a CSV file using AWK by breaking down the process step-by-step. Understanding the Problem Let’s start by examining the problem at hand. Suppose you have a CSV file containing records of students and their details, as shown below: [[See Video to Reveal this Text or Code Snippet]] In this example, we want to change the value 6767 in the third column of the second row to 0000. Here, the first row serves as a header, which means that the data we want to edit is located in Row 3 (as row numbering starts from 1, the header is not counted). The Solution Using AWK To execute this operation using AWK, follow the steps below: Step 1: Choose the correct field separator Since the CSV file uses a comma , to separate values, we need to inform awk to use this delimiter. We do this by setting the field separator option -F,. Step 2: Define the output field separator (if necessary) You may want to keep the output format the same as the input, so we define the output field separator as well with -v OFS=,. Step 3: Specify the row and column conditions In the command, we target the specific row and column where we want the change to occur. Step 4: Use the command Now, let’s put this all together into an AWK command to make the change. You can execute the following command in a terminal: [[See Video to Reveal this Text or Code Snippet]] Breakdown of the Command: awk: This invokes the AWK command. -F,: Sets the field separator to a comma. -v OFS=,: Sets the output field separator to a comma as well. NR==3: Checks if the current line number is 3 (which is the second row of data). {$3="0000"}: Updates the value of the third column to 0000 on the specified row. 1: This is a shorthand way in AWK to print the current record. Step 5: Review the Output After running the command, you should get the following output: [[See Video to Reveal this Text or Code Snippet]] Conclusion Using the awk command is a powerful way to modify specific values in a CSV file based on their positional context. By following the outlined steps, you can easily change any value located at a particular intersection of a column and row. This method is beneficial for quickly manipulating data without needing more complex scripting or programming solutions. Make sure to practice with different datasets to become comfortable using AWK for various tasks related to text processing and data manipulation!