What sed command do on CLI?

What sed command do on CLI?

Hey Toby

The sed command in UNIX, short for “stream editor,” is a versatile text-processing tool that operates on input streams or files. It can perform a wide range of operations on text, with its most common use being for substitution and find-and-replace tasks. Some key functionalities of the sed command include:

  1. Substitution: One of the primary uses of sed is to perform substitutions within text. It allows you to specify a pattern to search for and a replacement string, and it will replace all occurrences of the pattern with the replacement string.

  2. Find and Replace: sed can efficiently search for patterns in text and replace them with specified content. This is particularly useful for making systematic changes in large files or streams.

  3. Insertion and Deletion: sed enables you to insert lines before or after specific patterns or delete lines that match certain criteria. This is valuable for selectively modifying text files or stream content.

  4. Global Operations: By default, sed performs its operations on each occurrence of the pattern within a line. However, it can be configured to apply changes globally to every occurrence within a line by using the g flag in substitution commands.

  5. Regular Expressions: sed supports regular expressions, allowing you to perform complex pattern matching and manipulation. This makes it powerful for advanced text processing tasks.

  6. In-Place Editing: You can use the -i option to perform in-place editing of files, meaning sed directly modifies the content of the input files, making it suitable for automated batch processing.

  7. Scripting: sed can be used with scripts to perform multiple text-processing tasks in a sequence. This is helpful for automating complex text transformations.

In summary, the sed command in UNIX is a versatile stream editor that excels at text manipulation, making it a valuable tool for tasks such as data cleaning, log analysis, and batch text processing. Its ability to handle regular expressions and perform substitutions and find-and-replace operations makes it a powerful asset in the UNIX command-line toolbox.