ChatGPT:

In PowerShell, you can use the -replace operator to perform regular expression-based text replacements, which is somewhat similar to using sed with the -r option in Unix-like systems. However, PowerShell doesn't have an exact equivalent for the -r option in sed, which enables extended regular expressions.

Here's how you can use the -replace operator in PowerShell to perform regular expression-based text replacements:

# Basic usage of -replace without extended regular expressions
$text = "Hello, World!"
$newText = $text -replace "Hello", "Hi"

If you specifically need extended regular expressions, you can use the [regex]::Replace() method, which supports extended regular expressions:

# Using [regex]::Replace() with extended regular expressions
$text = "Hello, World!"
$newText = [regex]::Replace($text, "H.llo", "Hi")

In this example, we're using the . to match any character in place of the letter o, which is an example of extended regular expression syntax.

Keep in mind that while PowerShell's -replace operator and [regex]::Replace() method provide regular expression capabilities, they don't support all the features of extended regular expressions that -r does in sed. PowerShell's regular expressions are based on the .NET Framework's regular expression engine, which is different from the one used in sed.

In PowerShell, you can use the Select-String cmdlet to perform operations similar to grep in Unix-like systems. To achieve the equivalent of grep -nEHI, you can combine several parameters and options in Select-String as follows:

• -Pattern: Specifies the regular expression pattern to search for.
• -Path: Specifies the file(s) to search in.
• -AllMatches: Returns all matches in each line (equivalent to -E in grep).
• -IgnoreCase: Performs a case-insensitive search (equivalent to -i in grep).
• -LineNumber: Shows line numbers for matched lines (equivalent to -n in grep).

Here's how you can use Select-String with these options to replicate the behavior of grep -nEHI:

Select-String -Pattern 'your_pattern' -Path 'your_files' -AllMatches -IgnoreCase | Select-Object -Property LineNumber,Line

Replace 'your_pattern' with the regular expression you want to search for, and 'your_files' with the path to the file(s) you want to search in.

Here's a breakdown of what each part does:

• Select-String -Pattern 'your_pattern' -Path 'your_files' -AllMatches -IgnoreCase searches for the specified pattern in the specified file(s) with case-insensitivity and returns all matching occurrences.
• Select-Object -Property LineNumber,Line then formats the output to include line numbers and the matched lines.

This PowerShell command should give you similar functionality to grep -nEHI in Unix-like systems.

could we use Python to implement the grep like https://stackoverflow.com/questions/1921894/grep-and-python?

Basically, the grep -nEHI '[[:blank:]]$' behaves differently in Windows, Linux and Windows WSL. From the time being, the search only works in Linux.

In Windows, I have to use [[:space:]] for the match. in WSL, [[:blank:]] doesn't match anything and [[:space:]] would print lots of empty lines.

Windows grep using https://gnuwin32.sourceforge.net/packages/grep.htm:

WSL:

could we use Python to implement the grep like stackoverflow.com/questions/1921894/grep-and-python?

I think so! There's going to be some performance penalties, but better for it to work than failing I guess