powershell replace $_ if criteria meets

Question

I read a xml file and want to replace three strings.

My Code:

foreach ($file in Get-ChildItem $files){
 (Get-Content $file) | Foreach-Object {
  $_ -replace 'TABLE_NAME="\$ZoneProdukt\$', ('TABLE_NAME="' + $ZONPRODLANG)`
    -replace 'OPTION="Copy" ', '' `
    -replace ('<JOB ','<JOB TIMETO="TEST" ') | ? {$_ -notlike "*TIMETO=`""}
 } |  Set-Content ($destination_folder + $file.name)
}

the last replace provides only the half of the result I expect.

If there are lines containing "JOB" and "TIMETO" they will not be displayed (because of Where-Object)

How to keep lines if the mentioned "TIMETO"-Attribute already exists?

examples:

source line in file (without "TIMETO"):

<JOB JOBISN="30" USER="testuser">

correct replace:

<JOB TIMETO="TEST" JOB JOBISN="30" USER="testuser">

....

source line in file (with "TIMETO"):

<JOB JOBISN="30" USER="testuser" TIMETO="0400">

replace -> this line will not be displayed !!

..

thanks in advance! br danijel

[Do not parse XML with regex](http://stackoverflow.com/a/1732454/1630171). — Ansgar Wiechers, Mar 15 '18 at 14:35
Wrap your entire `-replace` logic with parenthesis. Or better yet, use the `.Replace()` string method, since you're not doing anything special with regex. — Maximilian Burszley, Mar 15 '18 at 14:35
@AnsgarWiechers I will never not upvote a link to that post. — Maximilian Burszley, Mar 15 '18 at 14:36
@TheIncorrigible my posted code is only a part of entire replace - there are more replaces which include regex — Danijel de Vasco, Mar 15 '18 at 14:40
Use regex where it's needed, otherwise you're using a hammer on a screw. — Maximilian Burszley, Mar 15 '18 at 14:41
*Why not? because of performance impact?* That's explained in [this answer to the same question](https://stackoverflow.com/a/1758162/1630171). And because PowerShell already comes with a ready-made XML parser that will do all the hard work for you. Regular expressions are just the wrong tool for dealing with XML, unless you have a *very* simple, clear-cut problem with *very* well-defined input. — Ansgar Wiechers, Mar 15 '18 at 14:51

G42 · Answer 1 · 2018-03-15T15:18:56.217

1

You could use an if-statement in your ForEach-Object:

foreach ($file in Get-ChildItem $files){
 (Get-Content $file) | Foreach-Object {
    if($_ -like "*TIMETO=`""){
      $_ -replace 'TABLE_NAME="\$ZoneProdukt\$', ('TABLE_NAME="' + $ZONPRODLANG)`
        -replace 'OPTION="Copy" ', '' `
    }else{
      $_ -replace 'TABLE_NAME="\$ZoneProdukt\$', ('TABLE_NAME="' + $ZONPRODLANG)`
        -replace 'OPTION="Copy" ', '' `
        -replace ('<JOB ','<JOB TIMETO="TEST" ')
    }
 } |  Set-Content ($destination_folder + $file.name)
}

Manipulating xml using regex is generally bad practice. You should use Get-Content and cast as [xml], which will allow you to manipulate the object. Check out this this MSDN demo.

edited Mar 15 '18 at 15:18

answered Mar 15 '18 at 14:37

G42

9,791
2
19
34

the problem of that solution is that the other replaces(e.g. table_name and option) must be done regardless of whether "timeto" is matched in line. – Danijel de Vasco Mar 15 '18 at 14:58
@DanijeldeVasco Quick and dirty solution in edit. Seriously though, consider the object approach. – G42 Mar 15 '18 at 15:19

powershell replace $_ if criteria meets

1 Answers1