---------------
for i in `sudo netstat -tulpn | awk '{print $7}' | cut -d/ -f1`; do echo "------ $i -------"; ps -p $i -o args=; done
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----> Detailed Explanation
1. sudo netstat -tulpn:
- sudo: This command is run with superuser privileges, which is necessary to view all network connections and the processes associated with them.
- netstat: A command-line tool that displays network connections, routing tables, interface statistics, and more.
- -tulpn: These options specify what information to display:
- -t: Show TCP connections.
- -u: Show UDP connections.
- -l: Show only listening sockets.
- -p: Show the process ID (PID) and name of the program to which each socket belongs.
- -n: Show numerical addresses instead of resolving hostnames.
This command lists all active TCP and UDP connections along with the associated processes.
2. | awk '{print $7}':
- The output of `netstat` is piped (`|`) into `awk`, a text processing tool.
- '{print $7}': This command extracts the seventh column from the `netstat` output, which contains the PID and program name in the format `PID/ProgramName`.
3. | cut -d/ -f1:
- The output from `awk` is further piped into `cut`, which is used to split the string.
- -d/: Specifies the delimiter as `/`.
- -f1: Extracts the first field, which is the PID of the process (the part before the `/`).
4. for i in ...; do ...; done:
- This is a `for` loop that iterates over each PID extracted from the previous commands.
- $i: Represents the current PID in each iteration of the loop.
5. echo "------ $i -------":
- This command prints a separator line with the current PID, making the output more readable.
6. ps -p $i -o args=:
- ps: A command that reports a snapshot of current processes.
- -p $i: Specifies to show information for the process with the PID stored in `$i`.
- -o args=: Customizes the output to show only the command line arguments of the process, omitting the header.
----> Summary of Functionality
This command effectively does the following:
- Retrieves a list of all listening TCP and UDP connections along with their associated processes.
- Extracts the PIDs of these processes from the output of `netstat`.
- For each PID**, it prints the PID and the command line arguments used to start the process.
----> Example Output Interpretation
When you run this command, the output might look something like this:
---------------
------ 1234 -------
/usr/bin/python3 /path/to/script.py
------ 5678 -------
/usr/sbin/nginx -g daemon off;
---------------
In this example:
- The first line indicates that the process with PID `1234` is running a Python script.
- The second line shows that the process with PID `5678` is an instance of Nginx.
----> Conclusion
This command is useful for system administrators or users who want to monitor which processes are listening on network ports and what commands were used to start those processes. It combines several powerful command-line tools to provide a comprehensive view of network activity on the system
