CODEWITHSUNDEEP
powershellawkpowershell-7.3
user20682592
user20682592

Reputation:

How to convert this awk command to PowerShell native?

The original code was this:

curl -sL https://ftp.apnic.net/stats/apnic/delegated-apnic-latest | \
grep "apnic|JP|ipv4" | \
awk -F '|' '{ printf("%s/%d\n", $4, 32-log($5)/log(2)) }' | \
tee JP_IPv4.txt

I wanted to convert it to PowerShell, this is how far I got:

Invoke-WebRequest -Uri "https://ftp.apnic.net/stats/apnic/delegated-apnic-latest" |     
Select-String -Pattern "afrinic\|ZA\|ipv6" -ca | Select-Object -exp line |

I need to figure out how to convert the last part that uses awk command to PowerShell.

I use PowerShell 7.3

Upvotes: 1

Views: 128

Answers (1)

Mathias R. Jessen
Mathias R. Jessen

Reputation: 174815

The awk script appears to calculate the subnet prefix length from the network size.

You can replace the awk log(...) function call with [Math]::Log(...) in PowerShell to perform the exact same calculation:

# this takes care of the `curl` part
Invoke-WebRequest -Uri "https://ftp.apnic.net/stats/apnic/delegated-apnic-latest" -OutFile delegated_networks.txt

# this takes care of the `grep` part
Get-Content delegated_networks.txt |Where-Object {$_ -like 'apnic|JP|ipv4|*'} 

# this emulates the `awk | tee` part
$data|ForEach-Object {
  # -F '|'
  $cells = $_.Split('|')
  # '{ printf("%s/%d\n", $4, 32-log($5)/log(2)) }'
  '{0}/{1}' -f $cells[3],(32 - [Math]::Log($cells[4])/[Math]::Log(2))
} |Tee-Object -FilePath JP_ipv4.txt

As @mklement0 kindly points out, you can also combine the log-conversion operation into a single call in PowerShell:

PS ~>[Math]::Log(4096)/[Math]::Log(2)
12
PS ~>[Math]::Log(4096, 2)
12

Upvotes: 2

Related Questions