#----------------------------------------------------------------
# Cat.ps1
#----------------------------------------------------------------
param
(
  [string]$filespec = $null,
  [bool]$number = $false,  # number output lines
  [bool]$number_nonblank = $false, # Number nonblank output lines
  [bool]$show_ends = $false, # Display $ at end of each line
  [bool]$squeeze_blank = $false, # never more than one single blank line
  [bool]$show_tabs = $false # display TAB characters as ^I
);

#----------------------------------------------------------------
# function Do-Cat
#----------------------------------------------------------------
function Do-Cat()
{
  param
  (
    [string]$filespec = $null,
    [bool]$number = $false,  # number output lines
    [bool]$number_nonblank = $false, # Number nonblank output lines
    [bool]$show_ends = $false, # Display $ at end of each line
    [bool]$squeeze_blank = $false, # never more than one single blank line
    [bool]$show_tabs = $false # display TAB characters as ^I
  );
  
  if ( $number_nonblank ) { $number = $false; }
  
  $files = @(Get-ChildItem $filespec -ErrorAction SilentlyContinue);
  if ( $files.Length -gt 0 )
  {
    foreach ($file in $files)
    {
      $content = @(Get-Content -Path $file);
      
      $cur_number = 1;
      $last_line = $null;
      
      # iterate through the lines in the file
      for ($i=0; $i -lt $content.Length; $i++)
      {
        $line = $content[$i];
        
        # If sqeezing blanks, if the this and last lines are empty, 
        # continue to next line
        if ( $squeeze_blank )
        {
          if ( ($last_line -ne $null) -and ($last_line.Length -eq 0) -and ($line.length -eq 0) )
          {
            continue;
          }
        }
        
        # Append "$" to ends of lines
        if ( $show_ends )
        {
          $line = $line + "$";
        }
        
        # Replace tabs with "^I"
        if ( $show_tabs )
        {
          $line = $line.Replace("`t", "^I");
        }
        
        # Prefix with numbers.  number_nonblank overrides number
        if ( $number_nonblank )
        {
          if ( $line.Length -gt 0 )
          {
            $line = "{0,6}  $line" -f $cur_number;
            $cur_number++;
          }
        }
        elseif ( $number )
        {
            $line = "{0,6} $line" -f $cur_number;
            $cur_number++;
        }
        
        # Keep last line for next pass
        $last_line = $content[$i];
        
        $line;
      }
      
    }
  }
  else
  {
    "No files matching pattern '$filespec' found!";
  }
}

Do-Cat -filespec $filespec -number $number -number_nonblank $number_nonblank `
  -show_ends $show_ends -squeeze_blank $squeeze_blank -show_tabs $show_tabs;