How to search for file content in Linux?

In Linux, you can use the following command to search for file contents:

1. grep command: search for lines matching a specific pattern in a file.
2. Syntax: grep [options] pattern file
3. For example, you can use the command grep “example” file.txt to search for lines containing the string “example” in the file file.txt.
4. Find command: search for files that meet the conditions in the specified path.
5. Syntax: locate path [options]
6. For example, to search for files containing the string “example” in the current directory and its subdirectories, you can use the command find . -type f -exec grep “example” {} +.
7. ack command: an advanced file search tool, similar to grep, but by default it will ignore version control files and temporary files.
8. syntax: ack [options] mode
9. For example, to search for files containing the string “example” in the current directory and its subdirectories, you can use the command ack “example”.
10. ag command: Another advanced file search tool, similar to ack, but faster and more powerful.
11. Syntax: ag [options] mode
12. For example, to search for files containing the string “example” in the current directory and its subdirectories, you can use the command ag “example”.

These commands can all be used for more complex searches based on different options, and their detailed usage and option explanations can be viewed using the ‘man’ command.