Extract certain values from string in .txt files with PowerShell

Question

Im trying to extract certain values from multiple lines inside a .txt file with PowerShell. Im currently using multiple replace and remove cmd's but it doesn't work as expected and is a bit too complex. Is there a more simple way to do this?

My script:

$file = Get-Content "C:\RS232_COM2*"

foreach($line in $file){
$result1 = $file.replace(" <<<  [NAK]#99","")
$result2 = $result1.remove(0,3) #this only works for the first line for some reason...
$result3 = $result2.replace("\(([^\)]+)\)", "") #this should remove the string within paranthesis but doesn't work

.txt file:

29 09:10:16.874 (0133563471) <<<  [NAK]#99[CAR]0998006798[CAR]
29 09:10:57.048 (0133603644) <<<  [NAK]#99[CAR]0998019022[CAR]
29 09:59:56.276 (0136542798) <<<  [NAK]#99[CAR]0998016987[CAR]
29 10:05:36.728 (0136883233) <<<  [NAK]#99[CAR]0998050310[CAR]
29 10:55:36.792 (0139883179) <<<  [NAK]#99[CAR]099805241D[CAR]0998028452[CAR]
29 11:32:16.737 (0142083132) <<<  [NAK]#99[CAR]0998050289[CAR]0998031483[CAR]
29 11:34:16.170 (0142202566) <<<  [NAK]#99[CAR]0998034787[CAR]
29 12:01:56.317 (0143862644) <<<  [NAK]#99[CAR]0998005147[CAR]

The output i expect:

09:10:16.874 [CAR]0998006798[CAR]
09:10:57.048 [CAR]0998019022[CAR]
09:59:56.276 [CAR]0998016987[CAR]
10:05:36.728 [CAR]0998050310[CAR]
10:55:36.792 [CAR]099805241D[CAR]0998028452[CAR]
11:32:16.737 [CAR]0998050289[CAR]0998031483[CAR]
11:34:16.170 [CAR]0998034787[CAR]
12:01:56.317 [CAR]0998005147[CAR]

$result1 = $file.replace -> $result1 = $line.replace

Mathias R. Jessen
– Mathias R. Jessen

2016-11-29 11:47:33 +00:00
Commented Nov 29, 2016 at 11:47 — Mathias R. Jessen
– Mathias R. Jessen, Commented Nov 29, 2016 at 11:47

Avshalom · Accepted Answer · 2016-11-29 11:54:21Z

1

or more simple:

$Array = @()
foreach ($line in $file)
{
$Array += $line -replace '^..\s' -replace '\s\(.*\)' -replace '<<<.*#\d+'
}
$Array

edited Nov 29, 2016 at 11:54

answered Nov 29, 2016 at 11:48

Avshalom

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Wiktor Stribiżew · Accepted Answer · 2016-11-29 11:58:30Z

Another option is to just grab the parts of a line you need with one regex and concat them:

$input_path = 'c:\data\in.txt'
$output_file = 'c:\data\out.txt'
$regex = '(\d+(?::\d+)+\.\d+).*?\[NAK]#99(.*)'
select-string -Path $input_path -Pattern $regex -AllMatches | % { $_.Matches } | % { [string]::Format("{0} {1}", $_.Groups[1].Value, $_.Groups[2].Value) } > $output_file

The regex is

(\d+(?::\d+)+\.\d+).*?\[NAK]#99(.*)

See the regex demo

Details:

(\d+(?::\d+)+\.\d+) - Group 1: one or more digits followed with 1+ sequences of : and one or more digits, then . and again 1+ digits
.*?\[NAK]#99 - any 0+ chars other than newline as few as possible up to the first [NAK]#99 literal char sequence
(.*) - Group 2: the rest of the line

After we get all matches, the $_.Groups[1].Value concatenated with $_.Groups[2].Value yield the expected output.

Mathias R. Jessen · Accepted Answer · 2016-11-29 12:03:06Z

1

Multiple issues.

Inside the loop you reference $file rather than $line. In the last operation, you're using the String.Replace() method with a regex pattern - something that method doesn't understand - use the -replace operator instead:

$file = Get-Content "C:\RS232_COM2*"

foreach($line in $file){
    $line = $line.Replace(" <<<  [NAK]#99","")
    $line = $line.Remove(0,3)

    # now use the -replace operator and output the result
    $line -replace  "\(([^\)]+)\)","" 
}

You could do it all in one regular expression replacement:

$line -replace '\(\d{10}\)\ <<<\s+\[NAK]\#99',''

edited Nov 29, 2016 at 12:03

answered Nov 29, 2016 at 11:53

Mathias R. Jessen

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1 Comment

Tehc Over a year ago

Thank you very much. Easy to understand and good explanation.

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