Technology and coding related articles
Sometimes you need to test whether two machines can connect with each other using TCP/IP. I personally need to do this when debugging client/server applications to rule out network issue. There is a useful command tool called nc. To test the connection from client B to server A, you need to start nc listening to…
There are times when you need to find some specific substring in files and replace them with something else. Let’s say, you want to find all occurrences of substring “foo” and replace them with “bar” in all java files under current directory. Here’s how you can do it on Linux (cd to your target directory…
There are many times that you need to calculate total number of lines in your coding project. Here’s an example of how to do this on Linux or Unix like systems: Note the example above shows how to calculate total lines of all the JavaScript (.js) files. If your project are using other languages, you…
To check opened ports on Linux, you can run the following command: Here is an example of the output: In addition, you can run this command to show active internet connections (both servers and established): Here’s an example of the output: