directories

If you ever need to generate a list of subdirectories in a directory in Scala, here's one way to do it:

def getListOfSubDirectories(directoryName: String): Array[String] = {
  return (new File(directoryName)).listFiles.filter(_.isDirectory).map(_.getName)
}

I intentionally wrote that function in a short, "Scala like" style, but you can expand it to multiple lines, if you prefer.

To demonstrate the use of this directory-listing function, you can print all your subdirectories like this:

Unix/Linux find "patterns" FAQ: How do I find files or directories that don't match a specific pattern (files not matching a regex pattern, or filename pattern)?

In my case I just ran into a situation where I needed to find all files below the current subdirectory that are NOT named with the filename pattern "*.html" . Fortunately with the newer Unix/Linux find syntax this solution is pretty easy, you just include the "-not" argument, like this:

Linux move/rename files FAQ: How do I rename or move Linux files and directories?

You use the Linux mv command to rename or move Linux files and directories. Let's look at some move/rename examples.

Using Linux mv to rename files and directories

At its most basic, here's how you rename a Linux file:

mv Chapter1 Chapter1.old

This mv command serves the purpose of renaming the file Chapter1 to the new filename Chapter1.old.

You can use the same technique to rename directories, like this:

Linux file copy FAQ: How do I copy Linux files and directories? (Or, Can you share some cp command examples?)

You use the Linux cp command to copy Linux files and directories. Let's look at some copy examples to see how this works.

Using Linux cp to copy files

At its most basic, here's how you copy a Linux file:

cp Chapter1 Chapter1.bak

This cp command copies the original file named Chapter1 to the new file named Chapter1.bak. After issuing this command both your original file and the new file will be in the current directory.

Git empty directories FAQ: How do I add an empty directory to a Git repository?

Short answer - you can't. (See below for the workaround.) The design of the Git staging area only accounts for files, as described in the Git FAQ, and other books like Pro Git.

Git empty directories FAQ

Here's the text from the Git FAQ section, "Can I add empty directories to a Git repository":