Update 'README.md'

README.md

@@ -47,6 +47,22 @@ This creates `threads.html` and extracts all information into the directory.
 
 ## File Management
 
+### Search for a specific string in files using grep in a designated directory
+
+`grep -rl "search-string" /path/to/search/dir`
+
+    `-r`, `--recursive`: Enables recursive search in files.
+    `-R`, `--dereference-recursive`: Performs a recursive search and follows symlinks.
+    `--include=FILE_PATTERN`: Limits the search to files matching FILE_PATTERN.
+    `--exclude=FILE_PATTERN`: Excludes files and directories that match FILE_PATTERN.
+    `--exclude-from=FILE`: Excludes files that match any pattern listed in FILE.
+    `--exclude-dir=PATTERN`: Skips directories matching PATTERN.
+    `-L`, `--files-without-match`: Displays names of files with no matches.
+    `-l`, `--files-with-matches`: Shows names of files containing the search string.
+    `-i`, `--ignore-case`: Searches without considering case differences.
+    `-e`, `--regexp=PATTERN`: Searches using a specified pattern or multiple search strings.
+    `-w`, `--word-regexp`: Searches for the complete word. 
+
 ### List number of files (for instance, # of .mp4)
 
 ```ls *.mp4 | cat -n```