Gaurav » GIT

Context sensitive auto-completion using PowerShell, PowerTab and GIT

Gaurav — Mon, 13 Oct 2008 19:33:46 +0000

Powertab is an Awesome PowerShell TabExpansion extension. It extends the default PowerShell autocompletion and shows the results like:

The best part is that it is easily customizable.

One way to customize it is by editing it Tab Expansion database file which is located in your powershell profile directory:

TabExpansion.xml

To display some simple git commands in autocompletion all the following entries to it:

<Custom>
  <Filter>gitFilter>
  <Text>statusText>
  <Type>CustomType>
Custom>
<Custom>
  <Filter>gitFilter>
  <Text>add .Text>
  <Type>CustomType>
Custom>
<Custom>
  <Filter>gitFilter>
  <Text>pullText>
  <Type>CustomType>
Custom>
<Custom>
  <Filter>gitFilter>
  <Text>pushText>
  <Type>CustomType>
Custom>
<Custom>
  <Filter>gitFilter>
  <Text>commit -m ""Text>
  <Type>CustomType>
Custom>
<Custom>
  <Filter>gitFilter>
  <Text>commit -a -m ""Text>
  <Type>CustomType>
Custom>

To invoke this list add the following to TabExpansion.ps1 file which should be in the source directory:

'git(.*)' {
  if(Test-Path .git) {
    $global:dsTabExpansion.Tables['Custom'].select("filter = 'git' AND type = 'Custom'") | % {$_.text} | Invoke-TabItemSelector  -SelectionHandler $SelectionHandler
  }
}

This should be added in the Main tabcompletion block inside the switch statement. The function is basically matching the current command name with git and then invoking autocompletion.

Now when you type git then the output should look like below:

I am sure this is not the best way to do custom autocompletion but i couldn’t find an easier way.

This is all static stuff. To add dynamic autocompletion (like providing branch names) add following to the TabExpansion.ps1 file:

'git(.*)' {
  if(Test-Path .git) {
    # git checkout
    if($lastBlock -match 'git checkout'){
      git branch | %{ if($_ -match "^\*?\s*(.*)"){ $matches[1] } } | Invoke-TabItemSelector  -SelectionHandler $SelectionHandler
    }
    else{
      $global:dsTabExpansion.Tables['Custom'].select("filter = 'git' AND type = 'Custom'") | % {$_.text} | Invoke-TabItemSelector  -SelectionHandler $SelectionHandler
    }
  }
}

Now when you type git checkout then it should show the following in the autocomplete list:

This function checks if the user has entered git checkout as the command then it runs the git branch command, parses it and shows the result as autocomplete list.

Here are couple more commands that I wrote while trying this out:

'git(.*)' {
  if(Test-Path .git) {
    # git checkout
    if($lastBlock -match 'git checkout'){
      git branch | %{ if($_ -match "^\*?\s*(.*)"){ $matches[1] } } | Invoke-TabItemSelector  -SelectionHandler $SelectionHandler
    }
    
    # git add
    Elseif($lastBlock -match 'git add'){
      $s = $False ; git status | %{ if($s -eq $True -and $_ -match "^#\s{1,1}(\S.+)$"){ $matches[1] } ElseIf($_ -match 'Untracked files:'){ $s = $True } } | Invoke-TabItemSelector  -SelectionHandler $SelectionHandler
    }
    
    # git rm
    Elseif($lastBlock -match 'git rm'){
      git status | %{ if($_ -match "^#\s+deleted:\s+(\S.+)$"){ $matches[1] } } | Invoke-TabItemSelector  -SelectionHandler $SelectionHandler
    }
    
    else{
      $global:dsTabExpansion.Tables['Custom'].select("filter = 'git' AND type = 'Custom'") | % {$_.text} | Invoke-TabItemSelector  -SelectionHandler $SelectionHandler
    }
  }
}

These will autocomplete parameters for git add and git rm commands by running the git status command and parsing the output.

For example:

I think a lot more interesting stuff can be created using PowerTab and GIT.

Update 1:

Turns out as pointed by MOW that there is a much easier way to add custom expansions instead of editing the TabExpansion.xml file.

Just run this command inside PowerShell:

Invoke-TabExpansionEditor

It will open up a dialog box like:

Here custom items can be added by clicking the Custom link and then the database change can by saved by running the command:

Export-tabExpansionDataBase

Displaying GIT Branch on your PowerShell prompt

Gaurav — Sun, 12 Oct 2008 07:48:28 +0000

PowerShell is a command line shell like the command prompt (cmd.exe) but with a lot more features. It can be downloaded from here.

One of the features is that you can change the default prompt. Prompt can be changed by overriding the function with name “prompt”.

This function can be declared inside the PowerShell profile file which has the path:

C:\Users\Gaurav\Documents\WindowsPowerShell\Microsoft.PowerShell_profile.ps1

If the file does not exist then you will need to create this file. Declaring the following function inside the profile file will change the prompt.

function prompt {
  return "prompt> "
}

to:

Now, to display the git branch as a prompt change the function to the following:

function prompt {
  $host.ui.rawui.WindowTitle = $(get-location)
  
  $prompt_string = ""
  
  if(Test-Path .git) {
    $prompt_string = "GIT"
    git branch | foreach {
      if ($_ -match "^\*(.*)"){
        $prompt_string += $matches[1] + "> "
      }
    }
  }
  else{
    $prompt_string = "PS> "
  }
  
  Write-Host ($prompt_string) -nonewline -foregroundcolor yellow
  return " "
}

and the prompt will look like:

The code basically is checking if current directory is a git project. This can be done by checking if there is a directory with name “.git” in the current directory. If yes then it runs the “git branch” command and then passes the result through a regular expression to get the current branch.

Here is my full PowerShell prompt function:

$Global:CurrentUser = [System.Security.Principal.WindowsIdentity]::GetCurrent()
$UserType = "User"
$CurrentUser.Groups | foreach { if($_.value -eq "S-1-5-32-544") {$UserType = "Admin"} }
  
function prompt {
  if($UserType -eq "Admin") {
    $host.ui.rawui.WindowTitle = "" + $(get-location) + " : Admin"
    $host.UI.RawUI.ForegroundColor = "Yellow"
  }
  else {
    $host.ui.rawui.WindowTitle = $(get-location)
  }
  
  Write-Host("")
  
  $status_string = ""
  
  if(Test-Path .git) {
    $status_string = "GIT"
    git branch | foreach {
      if ($_ -match "^\*(.*)"){
        $status_string += $matches[1]
      }
    }
    
    $git_create_count = 0
    $git_update_count = 0
    $git_delete_count = 0
    
    git status | foreach {
      if($_ -match "modified:"){ 
        $git_update_count += 1
      }
      elseif($_ -match "deleted:"){ 
        $git_delete_count += 1
      }
      elseif($_ -match "added:"){ 
        $git_create_count += 1
      }
    }
    $status_string += " u:" + $git_update_count + " d:" + $git_delete_count + ">"
  }
  else{
    $status_string = "PS>"
  }
  
  Write-Host ($status_string) -nonewline -foregroundcolor yellow
  return " "
}

This function also displays updated and deleted files in the current git project.

Scripts execution in PowerShell is disabled?

If you just created the profile file then PowerShell may display the following error message when loading this profile we just created:

File C:\Users\Gaurav\Documents\WindowsPowerShell\Microsoft.PowerShell_profile.ps1 cannot be loaded because the execution of scripts is disabled on this system. Please see “get-help about_signing” for more details.
At line:1 char:2
+ . <<<< ‘C:\Users\Gaurav\Documents\WindowsPowerShell\Microsoft.PowerShell_profile.ps1′

This is because PowerShell does not allow the execution of scripts by default. To fix this open PowerShell in Admin mode and set the execution policy to unrestricted by running the following command:

   1: Set-ExecutionPolicy Unrestricted

Compiling and Installing GIT on windows under cygwin

Gaurav — Fri, 11 Apr 2008 19:56:10 +0000

Using GIT was one of the requirements of one of the project that I am doing. Here is how I installed GIT on Windows.

So What is GIT?

The supplied documentation of GIT says that:

Git is a fast, scalable, distributed revision control system with an unusually rich command set that provides both high-level operations and full access to internals.

Here is the link for the wikipedia entry.

Where can I download GIT?

Here is the link.

Before following the given steps you will need to install cygwin on your system, and add its bin directory to the system path (so that all the cygwin commands are available from inside the command prompt).

So after installing cygwin run setup.exe inside the cygwin installation folder and make sure the following modules are installed.

make
gcc c anc c++ compilers
openssl-devel
curl-devel
Any other dependencies that are missing..

All these packages are located inside the Devel branch of the package tree. Required dependencies will be selected automatically.

Click next to install selected packages.

Compiling GIT form source

Untar the GIT source you downloaded using the command “tar xvzf git-1.5.5.tar.gz” .

Navigate to the untarred directory using a command prompt. Now run the “make” command inside the GIT source directory.

If it runs successfully then run “make install”.

Before running the command make sure you have Perl (language) installed. You can check it by running the command:

perl -MCPAN -e 'shell'

and then running the following inside the cpan shell:

install blib

it should show no error. I am not sure if this is the best way to do this as I am not much of a Perl guy.

So as I mentioned before you need to run the following two command to make and install Perl:

   1: make
   2: make install

If these two steps complete successfully then your GIT is ready to go :). You can test this by running the “git” command. This command is located inside the “C:/cygwin/home/gaurav/bin”. You might to add this folder to the system path too.

Pre-configured version

Here is a cygwin version pre-configured to compile GIT. It is installed on my system and works fine. Cygwin 1.5.25 and GIT 1.5.5 are preinstalled in this archive. Just decompress this archive under folder “C:\cygwin” and add “C:\cygwin\bin” and “C:/cygwin/home/gaurav/bin” to your system path and GIT should work form any command window.

del.icio.us Tags: GIT,open source,perl,vista,windows,cygwin