PowerShell String.Split() Off-by-Method-Overload Error

This seemed to me an error and I and was on the point of raising it as a bug on the Powershell github repo:

PS> "\this".Split( [char]'\', [StringSplitOptions]::RemoveEmptyEntries).Length
# >> 2

Presumably it is because [StringSplitOptions]::RemoveEmptyEntries is coerced to a [char] and so the line is parsed as:

PS> "\this".Split( ([char]'\', [StringSplitOptions]::RemoveEmptyEntries) ).Length

Instead of as

PS> \this".Split( (,[char]'\'), [StringSplitOptions]::RemoveEmptyEntries).Length

If the first parameter is a string not a character then it works as expected:

PS> "\this".Split( '\', [StringSplitOptions]::RemoveEmptyEntries).Length
# >> 1

But the really unfortunate case is :

PS> "\this".Split( [System.IO.Path]::DirectorySeparatorChar, [StringSplitOptions]::RemoveEmptyEntries).Length
# >> 2

which results in

PS> "\this".Split( [System.IO.Path]::DirectorySeparatorChar, [StringSplitOptions]::RemoveEmptyEntries).[0]
# >> $null
# instead of
# >> "this"

It turns out that it’s fixed in Powershell 6 Beta; or to be more precise, it doesn’t happen in PowerShell 6. What changed is that the underlying .Net framework has added new overloads to String.Split():

string[] Split(char separator, System.StringSplitOptions options)                                                                                    
string[] Split(char separator, int count, System.StringSplitOptions options)                                                                         
string[] Split(string separator, System.StringSplitOptions options)                                                                                  
string[] Split(string separator, int count, System.StringSplitOptions options)                                                                       

Whereas PowerShell 5 only has these overloads available:

string[] Split(Params char[] separator)                                                                                                              
string[] Split(char[] separator, int count)                                                                                                          
string[] Split(char[] separator, System.StringSplitOptions options)                                                                                  
string[] Split(char[] separator, int count, System.StringSplitOptions options)                                                                       
string[] Split(string[] separator, System.StringSplitOptions options)                                                                                
string[] Split(string[] separator, int count, System.StringSplitOptions options)                                                                     

And so the best-match overload that PowerShell 6 chooses is different to PowerShell 5’s best match.

Using Windows keystrokes on a Mac

Alas. I’ve been using Windows so long that now I go back to the Mac and want Ctrl-C to work. Sad, but there it is. At last I found Karabiner, which does keyboard remapping, and created a set of Karabiner rules to map the main Windows Ctrl-keystrokes to the matching ⌘-keystroke on Mac:

Karabiner Rules for main Windows Ctrl-keystrokes on MacOs

Okay, so Ctrl-W isn’t strictly a windows keystroke. But who can work without Ctrl-W?

Karabiner Complex Rules Snippet

 
{
    "profiles": [
        {
            "complex_modifications": {
                "parameters": {  /* ... etc ... */ },
"README": "********************************************************************************************************",
"README": "*" COPY JUST THE ELEMENTS OF THIS "rules" array into your profiles.complex_modifications.rules array. "*",
"README": "********************************************************************************************************",
              
                "rules": [
                    {
                        "description": "Change Control+Z to Command+Z",
                        "manipulators": [ { "from": { "key_code": "z","modifiers": {"mandatory": ["control"],"optional": ["any"]}},"to": [{"key_code": "z","modifiers": ["command"]}],"type": "basic"}]
                    },
                    {
                        "description": "Change Control+X to Command+X",
                        "manipulators": [ { "from": { "key_code": "x","modifiers": {"mandatory": ["control"],"optional": ["any"]}},"to": [{"key_code": "x","modifiers": ["command"]}],"type": "basic"}]
                    },
                    {
                        "description": "Change Control+C to Command+C",
                        "manipulators": [ { "from": { "key_code": "c","modifiers": {"mandatory": ["control"],"optional": ["any"]}},"to": [{"key_code": "c","modifiers": ["command"]}],"type": "basic"}]
                    },
                    {
                        "description": "Change Control+V to Command+V",
                        "manipulators": [ { "from": { "key_code": "v","modifiers": {"mandatory": ["control"],"optional": ["any"]}},"to": [{"key_code": "v","modifiers": ["command"]}],"type": "basic"}]
                    },
                    {
                        "description": "Change Control+N to Command+N",
                        "manipulators": [ { "from": { "key_code": "n","modifiers": {"mandatory": ["control"],"optional": ["any"]}},"to": [{"key_code": "n","modifiers": ["command"]}],"type": "basic"}]
                    },
                    {
                        "description": "Change Control+S to Command+S",
                        "manipulators": [ { "from": { "key_code": "s","modifiers": {"mandatory": ["control"],"optional": ["any"]}},"to": [{"key_code": "s","modifiers": ["command"]}],"type": "basic"}]
                    },
                    {
                        "description": "Change Control+O to Command+O",
                        "manipulators": [ { "from": { "key_code": "o","modifiers": {"mandatory": ["control"],"optional": ["any"]}},"to": [{"key_code": "o","modifiers": ["command"]}],"type": "basic"}]
                    },
                    {
                        "description": "Change Control+Y to Command+Y",
                        "manipulators": [ { "from": { "key_code": "y","modifiers": {"mandatory": ["control"],"optional": ["any"]}},"to": [{"key_code": "y","modifiers": ["command"]}],"type": "basic"}]
                    },
                    {
                        "description": "Change Control+W to Command+W",
                        "manipulators": [ { "from": { "key_code": "w","modifiers": {"mandatory": ["control"],"optional": ["any"]}},"to": [{"key_code": "w","modifiers": ["command"]}],"type": "basic"}]
                    }
                ],
"README": "******************************************************************************************************",
"README": "******************************************************************************************************",
            /* ... etc ... */
            }
        }
    ]
}

Editing the Keyboard Map

This approach didn’t work for me. I’m not sure what I missed.

‘bash\r’: No such file or directory. Or, editing unix files on a Windows machine

'bash\r': No such file or directory

What does that mean, you ask yourself? It usually means you are editing *nix script files on a windows system, and then running the files on a *nix machine. For instance in docker, or a VM.

Your GUI solution is to use a text editor that allows you to save with unix line endings. `Notepad++` calls it, very reasonably, `’EOL conversion’`. Sublime text calls it `View->Line Endings`.

Your commandline solution in a bash shell on macos is sed -i.bak $'s/\r//' * and on linux the same but you don’t need the ansi-C quoting: sed -i.bak 's/\r//' *
A further complication if you are using git is that it keeps getting reset back to windows. You could fix this with `git config core.autocrlf false` but that may have other consequences which you don’t want to bother with.

Use a public docker image in AWS ECS

Amazon Web Services carefully explain how to use a private docker image in ECS, the Amazon container service. But fails to mention what repository URL to use for a dockerhub public repository. The answer is … none at all. Just the same as the docker CLI, if you specify just namespace/imagename for a container image, ECS will pull it from dockerhub.