For newer versions of Ruby, try:

* `__dir__` 

For older versions of Ruby (&lt; 2.0), the script being run can be found using:

* `File.dirname(__FILE__)` - relative path; or
* `File.expand_path(File.dirname(__FILE__))` - the absolute path.

_**Note:** Using `__dir__` will return the script path even after a call to `Dir.chdir`; whereas, using the older syntax may not return the path to the script._


# Use `__dir__`

As of Ruby 2.0, `__dir__` is the simplest way to get this. It

&gt; Returns the canonicalized absolute path of the directory of the file
&gt; from which this method is called.

See the [`__dir__`](http://ruby-doc.org/core-2.0.0/Kernel.html#method-i-__dir__) documentation, and &quot;[Why is \__FILE__ uppercase and \__dir__ lowercase?][1]&quot;.


  [1]: https://stackoverflow.com/questions/15190700/why-is-file-uppercase-and-dir-lowercase

use [`__dir__`][1]

`File.dirname(__FILE__)` is not a proper way to get directory where script is stored.

At start working directory and directory with script file is the same, but it may change.

For example:

    Dir.chdir(&#39;..&#39;) do
    	puts __dir__
    	puts File.expand_path(File.dirname(__FILE__))
    end

for script file stored in `/Desktop/tmp` running it will give output 

    /home/mateusz/Desktop/tmp
    /home/mateusz/Desktop

  [1]: http://ruby-doc.org/core-2.3.0/Kernel.html#method-i-__dir__

ENV[&quot;PWD&quot;] seems the simplest way for me under Linux.   I don&#39;t know of an OS-agnostic way.

I am trying to cast `IList` type to `List` type but I am getting error every time.

    List&lt;SubProduct&gt; subProducts= Model.subproduct;

`Model.subproduct` returns `IList&lt;SubProduct&gt;`.

Cast IList to List

If I have a base class with a virtual destructor. Has a derived class to declare a virtual destructor too?

    class base {
    public:
        virtual ~base () {}
    };

    class derived : base {
    public:
        virtual ~derived () {} // 1)
        ~derived () {}  // 2)
    };

Concrete questions:

 1. Is 1) and 2) the same? Is 2) automatically virtual because of its base or does it &quot;stop&quot; the virtualness?
 2. Can the derived destructor be omitted if it has nothing to do?
 3. What&#39;s the best practice for declaring the derived destructor? Declare it virtual, non-virtual or omit it if possible?

Are virtual destructors inherited?

Inspired by &quot;https://stackoverflow.com/questions/59895/can-a-bash-script-tell-which-directory-it-is-stored-in&quot;, what&#39;s the Ruby way to do this?


Can a Ruby script tell what directory it’s in?

<p>Inspired by "<a href="https://stackoverflow.com/questions/59895/can-a-bash-script-tell-which-directory-it-is-stored-in&#x22;" target="_blank" rel="noopener noreferrer">https://stackoverflow.com/questions/59895/can-a-bash-script-tell-which-directory-it-is-stored-in"</a>;, what's the Ruby way to do this?</p>


Ruby/Rails does lots of cool stuff when it comes to sugar for basic things, and I think there&#39;s a very common scenario that I was wondering if anyone has done a helper or something similar for.

       a = Array.new(5, 1)
    
       a.each_with_index do |x, i|
         if i == 0
           print x+1
         elsif i == (a.length - 1)
           print x*10
         else
            print x
         end
       end

Pardon the ugliness, but this gets at what one might want... is there a ruby way to do something to the first and last of a loop?

**[EDIT]** I think ideally this would be an extension on Array with parameters (array instance, all elements function, &lt;optional&gt; first elements function, &lt;optional&gt; last elements function)... but I&#39;m open to other thoughts.

Magic First and Last Indicator in a Loop in Ruby/Rails?

I have an array of hashes, @fathers.

    a_father = { &quot;father&quot; =&gt; &quot;Bob&quot;, &quot;age&quot; =&gt;  40 }
    @fathers &lt;&lt; a_father
    a_father = { &quot;father&quot; =&gt; &quot;David&quot;, &quot;age&quot; =&gt;  32 }
    @fathers &lt;&lt; a_father
    a_father = { &quot;father&quot; =&gt; &quot;Batman&quot;, &quot;age&quot; =&gt;  50 }
    @fathers &lt;&lt; a_father 

How can I search this array and return an array of hashes for which a block returns true?

For example:

    @fathers.some_method(&quot;age&quot; &gt; 35) #=&gt; array containing the hashes of bob and batman

Thanks.



How do I search within an array of hashes by hash values in ruby?

I am new to Ruby.  I&#39;m looking to import functions from a module that contains a tool I want to continue using separately.  In Python I would simply do this:

    def a():
        ...
    def b():
        ...
    if __name__ == &#39;__main__&#39;:
        a()
        b()

This allows me to run the program or import it as a module to use `a()` and/or `b()` separately.  What&#39;s the equivalent paradigm in Ruby?

`if __name__ == &#39;__main__&#39;` equivalent in Ruby

What is Rack middleware in Ruby? I couldn&#39;t find any good explanation for what they mean by &quot;middleware&quot;.


What is Rack middleware?

How do I download and save a binary file over HTTP using Ruby?

The URL is `http://somedomain.net/flv/sample/sample.flv`.

I am on the Windows platform and I would prefer not to run any external program.



How do I download a binary file over HTTP?

I have a C++/Obj-C background and I am just discovering Python (been writing it for about an hour).
I am writing a script to recursively read the contents of text files in a folder structure.

The problem I have is the code I have written will only work for one folder deep. I can see why in the code (see `#hardcoded path`), I just don&#39;t know how I can move forward with Python since my experience with it is only brand new.

**Python Code:**

    import os
    import sys
    
    rootdir = sys.argv[1]
    
    for root, subFolders, files in os.walk(rootdir):
    	
    	for folder in subFolders:
    		outfileName = rootdir + &quot;/&quot; + folder + &quot;/py-outfile.txt&quot; # hardcoded path
    		folderOut = open( outfileName, &#39;w&#39; )
    		print &quot;outfileName is &quot; + outfileName
    		
    		for file in files:
    			filePath = rootdir + &#39;/&#39; + file
    			f = open( filePath, &#39;r&#39; )
    			toWrite = f.read()
    			print &quot;Writing &#39;&quot; + toWrite + &quot;&#39; to&quot; + filePath
    			folderOut.write( toWrite )
    			f.close()
    			
    		folderOut.close()


Python recursive folder read

What is the difference between a script and a program? Most of the time I hear that a script is running, is that not a program? I am bit puzzled, can anybody elaborate on this?


Difference between a script and a program?

I am attempting to automate moving files from a folder to a new folder automatically every night using a bash script run from AppleScript on a schedule. I am attempting to write a bash script on Mac OSX, and it keeps failing. In short this is what I have (all my `echo`s are for error checking):

    #!/bin/bash
    folder = &quot;ABC&quot;
    useracct = &#39;test&#39;
    day = date &quot;+%d&quot;
    month = date &quot;+%B&quot; 
    year = date &quot;+%Y&quot;
    folderToBeMoved = &quot;/users/$useracct/Documents/Archive/Primetime.eyetv&quot;
    newfoldername = &quot;/Volumes/Media/Network/$folder/$month$day$year&quot;
    ECHO &quot;Network is $network&quot; $network
    ECHO &quot;day is $day&quot;
    ECHO &quot;Month is $month&quot;
    ECHO &quot;YEAR is $year&quot;
    ECHO &quot;source is $folderToBeMoved&quot;
    ECHO &quot;dest is $newfoldername&quot;
    mkdir $newfoldername
    cp -R $folderToBeMoved $newfoldername
    if [-f $newfoldername/Primetime.eyetv];
        then rm $folderToBeMoved;
    fi

Now my first problem is that I cannot set variables at all. Even literal ones where I just make it equal some literal. All my `echo`s come out blank. I cannot grab the day, month, or year either,it comes out blank as well.

I get an error saying that -f is not found.

I get an error saying there is an unexpected end of file.

I made the file and did a `chmod u+x scriptname.sh`

I&#39;m not sure why nothing is working at all. I am very new to this bash script on OSX, and only have experience with windows vbscript. Any help would be great, thanks!


Unable to set variables in bash script

I have a script in Bash called `Script.sh`, and it needs to know its own PID (i.e. I need to get PID inside the Script.sh ) 

Any idea how to do this ?


How does a Linux/Unix Bash script know its own PID?

I needed to write a script to enter multi-line input to a program (`psql`).

After a bit of googling, I found the following syntax works:

    cat &lt;&lt; EOF | psql ---params
    BEGIN;
    
    `pg_dump ----something`
    
    update table .... statement ...;
    
    END;
    EOF

This correctly constructs the multi-line string (from `BEGIN;` to `END;`, inclusive) and pipes it as an input to `psql`.

But I have no idea how/why it works, can some one please explain?

I&#39;m referring mainly to `cat &lt;&lt; EOF`, I know `&gt;` outputs to a file, `&gt;&gt;` appends to a file, `&lt;` reads input from file. 

What does `&lt;&lt;` exactly do?

And is there a man page for it?

How does &quot;cat &lt;&lt; EOF&quot; work in bash?

I keep getting myself in knots when I am manipulating paths and file names because I don’t follow a naming standard for path components.

Consider the following toy problem (Windows example, but hopefully the answer should be platform independent). You have been given the path of a folder:

```
C:\users\OddThinking\Documents\My Source\
```

You want to walk the folders underneath and compile all the .src files to .obj files.

At some point you are looking at the following path:

```
C:\users\OddThinking\Documents\My Source\Widget\foo.src

```

**How would you name the following path components?**

```
A. foo
B. foo.src
C. src
D. .src
E. C:\users\OddThinking\Documents\My Source\ (i.e. the absolute path of the root)
F. Widget\foo.src (i.e. the relative path of the file)
G. Widget\
H. C:\users\OddThinking\Documents\My Source\Widget\
I. C:\users\OddThinking\Documents\My Source\Widget\foo.src
```

Here is my attempt:

A. Base name? Basename?

B. File name? Filename? The difference is important when choosing identifier names, and I am never consistent here.

C. Extension?

D. Extension? Wait, that is what I called C. Should I avoid storing the dot, and just put it in when required? What if there is no dot on a particular file?

E. ?

F. ?

G. Folder? But isn’t this a Windows-specific term?

H. Path name? Pathname? Path?

I. File name? Wait, that is what I called C. Path name? Wait, that is what I called H.

What is the naming standard for path components?

If I have two `DirectoryInfo` objects, how can I compare them for semantic equality?  For example, the following paths should all be considered equal to `C:\temp`:

 * `C:\temp`
 * `C:\temp\`
 * `C:\temp\.`
 * `C:\temp\x\..\..\temp\.`

The following may or may not be equal to `C:\temp`:

 * `\temp` if the current working directory is on drive `C:\`
 * `temp` if the current working directory is `C:\`
 * `C:\temp.`
 * `C:\temp...\`

If it&#39;s important to consider the current working directory, I can figure that out myself, so that&#39;s not that important.  Trailing dots are stripped in windows, so those paths really should be equal - but they aren&#39;t stripped in unix, so under mono I&#39;d expect other results.

Case sensitivity is optional.  The paths **may or may not exist**, and the user **may or may not have permissions to the path** - I&#39;d prefer a fast robust method that doesn&#39;t require any I/O (so no permission checking), but if there&#39;s something built-in I&#39;d be happy with anything &quot;good enough&quot; too...

I realize that without I/O it&#39;s not possible to determine whether some intermediate storage layer happens to have mapped the same storage to the same file (and even with I/O, when things get messy enough it&#39;s likely impossible).  However, it should be possible to at least positively identify paths that are equivalent, regardless of the underlying filesystem, i.e. paths that necessarily would resolve to the same file (if it exists) on all possible file-systems of a given type.  The reason this is sometimes useful is (A) because I certainly want to check this first, before doing I/O, (B) I/O sometimes triggers problematic side-effects, and (C) various other software components sometimes mangle paths provided, and it&#39;s helpful to be able to compare in a way that&#39;s insensitive to most common transformations of equivalent paths, and finally (D) to prepare deployments it&#39;s useful to do some sanity checks beforehand, but those occur before the to-be-deployed-on system is even accessible.

How can I compare (directory) paths in C#?

I&#39;m trying to get cron to call in the correct PATHs. When I run a Python script from shell the script runs fine as it uses the PATHs set in bashrc but when I use cron all the PATHs are not used from bashrc. Is there a file I can enter the PATHs into for cron like bashrc or a way to call the PATHs from bashrc?

Sorry I don&#39;t think I worded this correctly, I can get the correct script to run (meaning the PATH to the script in crontab is not the problem here), it&#39;s just when that script is running I run a build and this uses the PATHs set in `.bashrc`. When I run the script when I&#39;m logged in, the `.bashrc` PATHs are pulled in. Since cron doesn&#39;t run in a shell per say it does not pull in `.bashrc`. Is there a way of pulling this in without having to write a bash script wrapper?

How to get CRON to call in the correct PATHs

Is there a way to extract the file name from the file full path (part of a file path) without the hassle of manipulating string?

The equivalent in Java would be:

    File f = new File (&quot;C:/some_dir/a&quot;)
    f.getName() //output a
    f.getFullAbsolutePath() //output c:/some_dir/a

Find file name from full file path

Example:

    absolute=&quot;/foo/bar&quot;
    current=&quot;/foo/baz/foo&quot;

    # Magic

    relative=&quot;../../bar&quot;

How do I create the magic (hopefully not too complicated code...)?


Convert absolute path into relative path given a current directory using Bash

I would like to know (using C#) how I can delete files in a certain directory older than 3 months, but I guess the date period could be flexible. 

Just to be clear: I am looking for files that are older than 90 days, in other words files created less than 90 days ago should be kept, all others deleted.


Delete files older than 3 months old in a directory using .NET

I&#39;m trying to delete a folder and all files and folders within that folder, I&#39;m using the code below and I get the error `Folder is not empty`, any suggestions on what I can do?

    try
    {
      var dir = new DirectoryInfo(@FolderPath);
      dir.Attributes = dir.Attributes &amp; ~FileAttributes.ReadOnly;
      dir.Delete();
      dataGridView1.Rows.RemoveAt(dataGridView1.SelectedRows[i].Index);
    }
    catch (IOException ex)
    {
      MessageBox.Show(ex.Message);
    }

C# delete a folder and all files and folders within that folder

We have accidentally deleted the &#39;tags&#39; folder from our Subversion repository where we only intended to delete one specific tag. What is the easiest way to get the &#39;tags&#39; folder back?

We use TortoiseSVN as our client and I thought that when I go to the repo browser and show log, there will be something like &quot;revert changes from this revision&quot; similarly to what you can see in a similar dialog on your working copy. But there is no such command there...

How to &quot;undelete&quot; a deleted folder in Subversion / TortoiseSVN?

I&#39;ve run into a few cases with WordPress installs with [Bluehost][1] where I&#39;ve encountered errors with my WordPress theme because the uploads folder `wp-content/uploads` was not present.

Apparently the Bluehost [cPanel][2] WordPress installer does not create this folder, though [HostGator][3] does.

So I need to add code to my theme that checks for the folder and creates it otherwise.

  [1]: https://en.wikipedia.org/wiki/Bluehost
  [2]: https://en.wikipedia.org/wiki/CPanel
  [3]: https://en.wikipedia.org/wiki/HostGator



Create a folder if it doesn&#39;t already exist

I have a project with git, and I just want to clone or pull a specific directory, like myproject/javascript  just like subversion does. &lt;br /&gt; 
make some changes, commit and push back again. &lt;br /&gt;
It&#39;s possible?

How to pull specific directory with git

I have a crontab running every hour. The user running it has environment variabless in the `.bash_profile` that work when the user runs the job from the terminal, however, obviously these don&#39;t get picked up by crontab when it runs.

I&#39;ve tried setting them in `.profile` and `.bashrc` but they still don&#39;t seem to get picked up. Does anyone know where I can put environment vars that crontab can pick up?


Where can I set environment variables that crontab will use?

Currently, I use &lt;code&gt;Path.GetTempPath()&lt;/code&gt; to figure out where to write my log files, but recently I came across a user&#39;s machine where the path returned was not what I expected.

Usually, the returned path is **C:\Documents and Settings\\[userid]\Local Settings\Temp**
but in this case, it was **C:\Temp**

This would not normally be a problem, but for some reason the user in question did not have access to write to **C:\Temp**

I double checked the environment variables, and the USER environment variable was pointing as expected to **C:\Documents and Settings\\[userid]\Local Settings\Temp**, whilst the SYSTEM environment variable was pointing to **C:\WINNT\Temp**.

So... where is &lt;code&gt;Path.GetTempPath()&lt;/code&gt; getting it&#39;s value from ? Group Policy? Registry?

I have Googled, but to no avail.

What determines the return value of Path.GetTempPath()?

In Ubuntu, I&#39;d like to switch my JAVA_HOME environment variable back and forth between Java 5 and 6.

I open a terminal and type in the following to set the JAVA_HOME environment variable:

    export JAVA_HOME=/usr/lib/jvm/java-1.5.0-sun

And in that same terminal window, I type the following to check that the environment variable has been updated:

    echo $JAVA_HOME

And I see **/usr/lib/jvm/java-1.5.0-sun** which is what I&#39;m expecting to see.  In addition, I modify ~/.profile and set the JAVA_HOME environment variable to /usr/lib/jvm/java-1.5.0-sun.

And now for the problem--when I open a new terminal window and I check my JAVA_HOME environment variable by typing in **echo $JAVA_HOME** I see that my JAVA_HOME environment variable has been reverted back to Java 6.  When I reboot my machine (or log out and back in, I suppose) the JAVA_HOME environment variable is set to Java 5 (presumably because of the modification I made in my ~/.profile).

Is there a way around this so that I can change my JAVA_HOME environment without having to log out and back in (AND make that environment variable change *stick* in all new terminal windows)?

Make $JAVA_HOME easily changable in Ubuntu

What characters are allowed in Linux environment variable names? My cursory search of man pages and the web did only produce information about how to work with variables, but not which names are allowed.

I have a Java program that requires an defined environment variable containing a dot, like `com.example.fancyproperty`. With Windows I can set that variable, but I had no luck setting it in linux (tried in SuSE and Ubuntu). Is that variable name even allowed?

Allowed characters in Linux environment variable names

How can I get the client IP address using PHP?

I want to keep record of the user who logged into my website through his/her IP address.


Content Type	Original Author	Original Content on Stackoverflow
Question	java.is.for.desktop	View Question on Stackoverflow
Solution 1 - Ruby	gaqzi	View Answer on Stackoverflow
Solution 2 - Ruby	Nathan Long	View Answer on Stackoverflow
Solution 3 - Ruby	reducing activity	View Answer on Stackoverflow
Solution 4 - Ruby	Shadowfirebird	View Answer on Stackoverflow

Can a Ruby script tell what directory it’s in?

Ruby Problem Overview

Ruby Solutions

Solution 1 - Ruby

Solution 2 - Ruby

Use `dir`

Solution 3 - Ruby

Solution 4 - Ruby

Are virtual destructors inherited?

Cast IList to List

Attributions

Ruby Problem Overview

Ruby Solutions

Solution 1 - Ruby

Solution 2 - Ruby

Use __dir__

Solution 3 - Ruby

Solution 4 - Ruby

Are virtual destructors inherited?

Cast IList to List

Attributions

Use `dir`