# 1.9 Sort and Uniq: Comparing and Manipulating File Content ## Comparing and Manipulating File Content with Sort and Uniq Continuing our exploration of command-line file manipulation, this part of the blog focuses on the `sort` and `uniq` commands. We'll delve into how these commands, when paired with regular expressions, can efficiently compare and manipulate file content. ## Sort Command The `sort` command is instrumental in arranging lines within a file, be it alphabetically or numerically. Regular expressions come into play when defining custom sorting criteria. **Example 1: Sort lines in a file alphabetically** ```bash sort filename.txt ``` **Example 2: Reverse sort lines based on the second column (numerically)** ```bash sort -k2,2nr data.txt ``` **Example 3: Sort lines based on a custom pattern (e.g., month abbreviation)** ```bash sort -t"-" -k2,2M -k3,3n dates.txt ``` **Example 4: Sort lines based on the last word in each line** ```bash sort -t" " -kNF file.txt ``` **Example 5: Sort lines ignoring leading whitespaces** ```bash sort -b data.txt ``` ## Uniq Command The `uniq` command, as the name suggests, is designed to identify and filter out repeated lines within a file. Regular expressions add depth to its functionality. **Example 1: Display only unique lines in a sorted file** ```bash sort data.txt | uniq ``` **Example 2: Count and display the number of occurrences of each line** ```bash sort logfile.txt | uniq -c ``` **Example 3: Display only repeated lines in a sorted file** ```bash sort data.txt | uniq -d ``` **Example 4: Display only unique lines, ignoring the first 5 characters** ```bash sort file.txt | uniq -s 5 ``` **Example 5: Display only the first occurrence of each repeated line** ```bash sort data.txt | uniq -u ``` By combining `sort` and `uniq` with regular expressions, you gain precise control over how data is ordered and filtered. These commands, when used in conjunction with the previously discussed ones, provide a comprehensive toolkit for efficient file content manipulation on the command line. Understanding these examples and experimenting with various patterns will empower you to handle a wide range of file manipulation tasks effectively. Regular expressions, as the common thread, tie together these commands into a cohesive and powerful set for text processing and analysis.
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Congratulations on completing module 1. You have learned a lot in this module and I hope you enjoyed it. Now you are ready to move on to module 2 and explore new topics. I look forward to hearing from you and wish you a happy learning experience.