[linux] Mastering 'sed' Command in Linux

Introduction to ‘sed’

sed stands for stream editor and is a powerful utility in Linux used for parsing and transforming text. It processes text line by line and allows for performing various operations like search, replace, insert, delete, etc. on text files or streams.

One of the key features of sed is its ability to use regular expressions for pattern matching, making it a versatile tool for text manipulation tasks.

Basic Syntax

The basic syntax for using sed is as follows:

sed OPTIONS 'command' filename

• OPTIONS: These can be used to modify the behavior of sed, like using -i to edit files in place.
• ‘command’: This is the operation you want to perform using sed.
• filename: The name of the file to be processed.

Example Codes

1. Searching and Replacing:

   sed 's/old_text/new_text/g' filename
   

   This command replaces all occurrences of ‘old_text’ with ‘new_text’ in the file.

2. Deleting Lines:

   sed '/pattern/d' filename
   

   This command deletes all lines containing ‘pattern’ in the file.

3. Inserting Text:

   sed '1i\New_line' filename
   

   This command inserts ‘New_line’ at the beginning of the file.

Versions and Compatibility

sed is a standard Unix utility and is available on all Unix-like systems, including Linux. The GNU version of sed is the most common one and offers additional features like extended regular expressions.

As sed operates on streams of text, it can be easily integrated into shell scripts and pipelines to automate text processing tasks efficiently.

Mastering sed can greatly enhance your text manipulation capabilities in Linux, making it a valuable tool for sysadmins, developers, and anyone working with text files.