CODEWITHSUNDEEP
powershellawk
PythonKiddieScripterX
PythonKiddieScripterX

Reputation: 517

Powershell equivalent of bash's $NF

Someone wanted me to convert his bash code into powershell. I thought I could do it until I came across a weird built in variable called $NF which I think reads the lines of the logger? I am not sure how it works but because of it, it stops me from converting this bash script into powershell.

The specific two lines I am having a hard time with: bash script

curl -c ./cookie -s -L "https://drive.google.com/uc?export=download&id=${fileid}" > /dev/null
curl -Lb ./cookie "https://drive.google.com/uc?export=download&confirm=`awk '/download/ {print $NF}' ./cookie`&id=${fileid}" > ${filename}

but I am not sure what to write for $NF in powershell. The other variables, I know how to convert, just not this built in $NF variable to download the item from google drive.

Upvotes: 1

Views: 328

Answers (2)

Tim Hanson
Tim Hanson

Reputation: 59

I think more to the point of the general question about awk's magic variable NF -- number of fields on the line -- and its use in $NF -- the field at the rightmost position on the line is to note that Powershell's arrays can reference the final position using the index -1. (Perhaps easily remembered with: indexes 1, 2, 3... are from the left; indexes -1, -2, -3 are from the right.)

So as an example this morning I used:

 ipconfig | Where-Object {$_ -match 'IPv4 Address'} | %{($_ -split "\s+")[-1]}

to extract the IP addresses from the rightmost positions.

(I haven't worked out the specific curl example above -- in powershell I usually use Invoke-WebRequest in place of curl, but I think I've answered the $NF question and solving the specific question could proceed from there.)

Upvotes: 1

Start-Automating
Start-Automating

Reputation: 8377

As @Cyrus commented, $NF belongs to awk, not Bash.

Good news though: it should make working thru the equivalent really easy, since you can just run awk from PowerShell.

Since you can also call curl directly, I'll just modify the example you have.

# Assigning this to a variable for readability
$curlArg = "https://drive.google.com/uc?export=download&confirm=$(
      <#

      This is a PowerShell subexpression.
      the output of this subexpression will be included in the string
      (multiple outputs will be separated by ' ' )
      Executables may return multiple lines of output (aka multiple outputs), but this case looks like it will only return one line.
      If you need to combine the .exe's output, try -join.
      #>
       awk '/download/ {print $NF}./cookie'
   )&id=$fileid"

curl -Lb ./cookie $curlArg > $filename

Hope this Helps

Upvotes: 2

Related Questions