How to find all files containing a specific text (string) on Linux?

To find all files containing a specific text string on Linux, use the grep command with appropriate options. Here are the most common methods:

1. Basic Search (Case-Sensitive)

Search for a string in all files under a directory (recursive):

grep -r "search_text" /path/to/directory

2. Case-Insensitive Search

Add the -i flag to ignore case:

grep -ri "search_text" /path/to/directory

3. List Only Filenames (No Match Text)

Use -l to show files that contain the text:

grep -rl "search_text" /path/to/directory

4. Exclude Binary Files

Skip binary files (e.g., images, executables) with -I:

grep -rI "search_text" /path/to/directory

5. Search for Whole Words Only

Match exact words (not substrings) with -w:

grep -rw "search_text" /path/to/directory

6. Use Regular Expressions

Enable extended regex with -E (e.g., patterns like error|warning):

grep -rE "error|warning" /path/to/directory

Examples

1. Search for “hello world” in the current directory (case-insensitive):

   grep -ri "hello world" .

2. Find files containing “localhost” in /etc (filenames only):

   grep -rl "localhost" /etc

3. Search for the exact word “error” in log files:

   grep -rw "error" /var/log

Alternative Tools

• ripgrep (rg): Faster and modern alternative to grep.

  rg "search_text" /path/to/directory

• ack: Designed for code searches (ignores binaries by default).

  ack "search_text" /path/to/directory

Key Options

Option	Description
-r	Search recursively in directories.
-i	Case-insensitive search.
-l	List filenames only (no match text).
-I	Ignore binary files.
-w	Match whole words only.
-n	Show line numbers of matches.

By combining these options, you can efficiently locate text in files on Linux!