remove empty lines from text file with PowerShell

Question

I know that I can use:

gc c:\FileWithEmptyLines.txt | where {$_ -ne ""} > c:\FileWithNoEmptyLines.txt

to remove empty lines. But How I can remove them with '-replace' ?

Why do you want to replace? And work on your acceptance rate — manojlds, Feb 10 '12 at 06:09
My answer removes empty lines with the `-replace` [comparison operator](http://technet.microsoft.com/en-us/library/dd315321.aspx). `Get-Content` doesn't have a replace parameter, so I'm assuming you're looking for a way to do it with the operator. — Andy Arismendi, Feb 10 '12 at 07:47

score 75 · Answer 1 · answered Jun 12 '12 at 18:32

75

I found a nice one liner here >> http://www.pixelchef.net/remove-empty-lines-file-powershell. Just tested it out with several blanks lines including newlines only as well as lines with just spaces, just tabs, and combinations.

(gc file.txt) | ? {$_.trim() -ne "" } | set-content file.txt

See the original for some notes about the code. Nice :)

answered Jun 12 '12 at 18:32

Randy Skretka

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I think on balance I prefer `(gc file.txt) | ? { -not $_.IsNullOrWhiteSpace() } | set-content file.txt` because it expresses the intent more clearly, but it amounts to the same thing. – Neil Barnwell Oct 20 '14 at 11:42
On brief glance, I do not seem to have the "IsNullOrWhiteSpace()" method on my strings...and...how could an instance method check for null? The posted answer works great though! – xdhmoore Jan 15 '17 at 19:39
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The IsNullOrWhiteSpace is a static method from System.String object the proper way to call it in PowerShell is as follow : `[String]::IsNullOrWhiteSpace({your string})`. The correct command line base on Neil Barnwell comment is as follow: `(gc file.txt) | ? { -not [String]::IsNullOrWhiteSpace($_) } | set-content file.txt` – LMA1980 Feb 14 '18 at 17:23

score 25 · Answer 2 · answered Mar 08 '16 at 16:54

This piece of code from Randy Skretka is working fine for me, but I had the problem, that I still had a newline at the end of the file.

(gc file.txt) | ? {$_.trim() -ne "" } | set-content file.txt

So I added finally this:

$content = [System.IO.File]::ReadAllText("file.txt")
$content = $content.Trim()
[System.IO.File]::WriteAllText("file.txt", $content)

score 9 · Answer 3 · answered Feb 10 '12 at 13:58

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You can use -match instead -eq if you also want to exclude files that only contain whitespace characters:

@(gc c:\FileWithEmptyLines.txt) -match '\S'  | out-file c:\FileWithNoEmptyLines

answered Feb 10 '12 at 13:58

mjolinor

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score 6 · Answer 4 · answered Aug 13 '15 at 16:16

6

Not specifically using -replace, but you get the same effect parsing the content using -notmatch and regex.

(get-content 'c:\FileWithEmptyLines.txt') -notmatch '^\s*$' > c:\FileWithNoEmptyLines.txt

answered Aug 13 '15 at 16:16

joel

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This worked like charm. I was attempting to remove VB6 comments from a file and this was the final command I used - `(Get-Content -Path ".\vbXML.cls") -replace "\'.*$", "" -notmatch "^\s*$" | Out-File ".\vbXML.uncommented.cls" -Append` – Siva Senthil May 24 '18 at 06:52

PollusB · Answer 5 · 2019-11-26T01:29:47.700

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To resolve this with RegEx, you need to use the multiline flag (?m):

((Get-Content file.txt -Raw) -replace "(?m)^\s*`r`n",'').trim() | Set-Content file.txt

edited Nov 26 '19 at 01:29

answered Oct 22 '19 at 20:23

PollusB

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score 1 · Answer 6 · edited Dec 19 '14 at 17:25

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(Get-Content c:\FileWithEmptyLines.txt) | 
    Foreach { $_ -Replace  "Old content", " New content" } | 
    Set-Content c:\FileWithEmptyLines.txt;

edited Dec 19 '14 at 17:25

Matt

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answered Nov 12 '13 at 07:43

Nonso

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score 1 · Answer 7 · answered May 16 '14 at 00:11

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This removes trailing whitespace and blank lines from file.txt

PS C:\Users\> (gc file.txt) | Foreach {$_.TrimEnd()} | where {$_ -ne ""} | Set-Content file.txt

answered May 16 '14 at 00:11

Luke Fowler

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score 1 · Answer 8 · answered Mar 08 '18 at 13:34

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If you actually want to filter blank lines from a file then you may try this:

(gc $source_file).Trim() | ? {$_.Length -gt 0}

answered Mar 08 '18 at 13:34

Max

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Edward Thomas · Answer 9 · 2019-05-17T05:47:04.007

file

PS /home/edward/Desktop> Get-Content ./copy.txt

[Desktop Entry]

Name=calibre Exec=~/Apps/calibre/calibre

Icon=~/Apps/calibre/resources/content-server/calibre.png

Type=Application*

Start by get the content from file and trim the white spaces if any found in each line of the text document. That becomes the object passed to the where-object to go through the array looking at each member of the array with string length greater then 0. That object is passed to replace the content of the file you started with. It would probably be better to make a new file... Last thing to do is reads back the newly made file's content and see your awesomeness.

(Get-Content ./copy.txt).Trim() | Where-Object{$_.length -gt 0} | Set-Content ./copy.txt

Get-Content ./copy.txt

>to fix the wrongness of ~/ path to the full path as this file should have here is a bonus `(Get-Content ./copy.txt).Replace("~/","/home/edward/") | Set-Content ./copy.txt` — Edward Thomas, May 17 '19 at 05:19

score 1 · Answer 10 · answered Feb 10 '12 at 06:16

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You can't do replacing, you have to replace SOMETHING with SOMETHING, and you neither have both.

answered Feb 10 '12 at 06:16

is the Poowershell support -remove "" to remove emply lines? – Suliman Feb 10 '12 at 06:39
No it's seems that it does not have support of "-remove". – Suliman Feb 10 '12 at 06:46
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You're talking apples and oranges. Remove and Replace are clearly different. What you have will basically work, but perhaps you are trying to rebuild the existing file but without the blanks. PS C:\> $text=get-content a.txt PS C:\> $text | where {$_} | out-file a.txt – Jeffery Hicks Feb 10 '12 at 13:22

score 0 · Answer 11 · answered Mar 24 '22 at 09:11

Get-Content returns immutable array of rows. You can covert this to mutable array and delete neccessary lines by index.Particular indexex you can get with match. After that you can write result to new file with Set-Content. With this approach you can avoid empty lines that powershell replace tool leaves when you try to replace smthing with "". Note that I dont guarantee perfect perfomance. Im not a professional powershell developer))

$fileLines = Get-Content $filePath
$neccessaryLine = Select-String -Path  $filePath -Pattern 'something'
if (-Not $neccessaryLine) { exit }
$neccessaryLineIndex = $neccessaryLine.LineNumber - 1
$updatedFileContent = [System.Collections.ArrayList]::new($fileLines)
$updatedFileContent.RemoveAt($neccessaryLineIndex)
$updatedHostsFileContent.RemoveAt($domainInfoLineIndex - 1)
$updatedHostsFileContent | Set-Content $hostsFilePath

Dan · Answer 12 · 2022-04-28T15:13:15.403

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Set-Content -Path "File.txt" -Value (get-content -Path "File.txt" | Select-String -Pattern '^\s*$' -NotMatch)

This works for me, originally got the line from here and added Joel's suggested '^\s*$': Using PowerShell to remove lines from a text file if it contains a string

edited Apr 28 '22 at 15:13

answered Apr 28 '22 at 14:45

Dan

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score 0 · Answer 13 · answered Feb 10 '12 at 06:37

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This will remove empty lines or lines with only whitespace characters (tabs/spaces).

[IO.File]::ReadAllText("FileWithEmptyLines.txt") -replace '\s+\r\n+', "`r`n" | Out-File "c:\FileWithNoEmptyLines.txt"

answered Feb 10 '12 at 06:37

Andy Arismendi

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remove empty lines from text file with PowerShell

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