Various search operation options on Centos

Search for files or directories:

In CentOS 7, you can use various commands and tools to search for files or folders. Here are some common methods:

1. Using the `find` command:

The `find` command is a powerful tool to search for files and directories based on various criteria.

To search for a file named `filename.txt` starting from the root directory (/), open a terminal and run:

find / -name "filename.txt"

Replace `"filename.txt"` with the name of the file you're looking for.

To search for a directory named `dirname`, use the same command:

find / -type d -name "dirname"

2. Using the `locate` command:

The `locate` command utilizes a pre-built database of files for faster searching.

First, make sure the `mlocate` package is installed:

sudo yum install mlocate

Then, update the database:

sudo updatedb

Finally, search for a file or directory:

locate filename.txt

locate dirname

Note that `locate` provides faster results but might not show the most up-to-date information as it depends on the last database update.

3. Using `grep` command (for specific text within files):

If you are looking for files containing specific text, you can use the `grep` command. For example, to search for the word "example" within all files in the current directory and its subdirectories:

grep -r "example" .

The `.` represents the current directory. You can replace it with a specific directory path.

4. Using `whereis` command (for system binaries and manuals):

The `whereis` command is helpful for finding the binary and source files of a command or application.

For example, to find the location of the `ls` command:

whereis ls

These methods should help you search for files and folders efficiently on CentOS 7. Choose the appropriate method based on your requirements.

Search by filename extension:

To search for files by their extension in CentOS 7, you can use the `find` command along with the `-name` option and a wildcard to specify the file extension. Here's how you can do it:

Let's say you want to search for files with the extension `.txt` in the `/home/user/documents` directory:

find /home/user/documents -type f -name "*.txt"

Explanation:

- `find`: The command to search for files and directories.

- `/home/user/documents`: The starting directory for the search. Replace this with the directory where you want to begin the search. If you don't know the directory name or path just use '/' instead of full path like 

find / -type f -name "*.txt"

- `-type f`: Specifies that we are only interested in files (not directories).

- `-name "*.txt"`: The `-name` option allows us to specify a pattern to match filenames. Here, we use the wildcard `*` to match any characters before the `.txt` extension. This way, it will find all files with the `.txt` extension.

You can adjust the file extension and the directory path as needed to search for different file types in different locations. If you want to search for different file extensions, simply change `*.txt` to the desired extension (e.g., `*.pdf`, `*.jpg`, etc.).