Count occurrence of strings in a log.file with PowerShell

Question

I need to get the occurrence of "failure" in a logfile. The thing is I need to get the occurrence of "failure" for each session block. What the log looks like:

---Session 1 
check 
check 
failure
failure 
check
----Session 2 
check 
failure 
check 
check 
----Session 3 
failure 
failure

What I've got so far is this:

$rows = Get-Childitem -Path E:\shell\lot.log  |
        Select-String -Pattern failure
$i = 0
foreach ($row in $rows) {
    $i++
}
echo $i

With that script I only get the total of the occurrences.

So there's only 1 log file, with multiple Session blocks? If so, why the use of -Recurse? — mklement0
– mklement0, Commented May 23, 2018 at 21:20
@mklement0 oh sorry i didnt delete it.I've edited it. Yes it has been multiple logs. For each session one. But now there is only one file. — RaWneZ
– RaWneZ, Commented May 23, 2018 at 21:24

Ansgar Wiechers · Accepted Answer · 2018-05-23 23:23:06Z

1

I would start a new counter whenever a line beginning with 3 or more consecutive hyphens occurs and collect the results in a hashtable.

$failcount = @{}

Get-Content 'E:\shell\lot.log' | ForEach-Object {
    if ($_ -match '^-{3,}(.*)') {
        $section = $matches[1].Trim()
        $failcount[$section] = 0
    } elseif ($_ -like '*failure*') {
        $failcount[$section]++
    }
}

answered May 23, 2018 at 23:23

Ansgar Wiechers

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G42 · Accepted Answer · 2018-05-23 22:07:12Z

0

I believe this will do it. Key part is to reset your counter after each session.

$rows = Get-Childitem -Path E:\shell\lot.log

$i = 0  # failure counter
$j = 1  # session counter

foreach($row in $rows){
    if($row -like "*Session 1"){
        # skip the first line. Edit: removed * as would skip session 10, 11 etc. assumes line ends with "session 1"
        continue
    }elseif($row -eq "failure){
        # if the row is equal to failure, count it
        $i++
    }elseif($row -like "*Session*"){
        # when you get to the end of a session, print the number of failures
        Write-Host "Session $j had $i failures"

        # ... and reset the failure counter 
        $i = 0

        # increment the session counter
        $j++
    }
}

edited May 23, 2018 at 22:07

answered May 23, 2018 at 21:33

G42

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4 Comments

RaWneZ Over a year ago

looks great. But when i execute it, there is no occurrence echo

G42 Over a year ago

Does your file have lines like ----Session 2 in it? echo is replaced by the native Write-Host.

RaWneZ Over a year ago

I know what write-host means :D yes it has, why?

G42 Over a year ago

It's just you wrote echo, I wasn't sure ;-). Hmm not sure why that elseif isn't being ran then...

TheMadTechnician · Accepted Answer · 2018-05-23 23:37:09Z

I'll add another option. Read the whole log file in with -Raw to get a multi-line string. Remove the ---- from the first line, and then split on 3 or more hyphens at the beginning of a line, this gets you each session as a multi-line string, then you could just output text or custom objects, or whatever you wanted with it. Split the multi-line string on new line characters, filter for 'failure', and do a count to get failures per session.

(GC E:\shell\lot.log -Raw) -replace '^-+' -split '(?<=[\r\n])---+'|%{
    '{0} had {1} failure(s)' -f ($_.split("`n")[0].Trim()),($_ -split '[\r\n]+'|?{$_ -match 'failure'}).Count
}

That would (given the sample provided) output:

Session 1 had 2 failure(s)
Session 2 had 1 failure(s)
Session 3 had 2 failure(s)

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