How would I change multiple filenames in Powershell? - powershell

Question

I am trying to remove parts of a name "- xx_xx" from the end of multiple files. I'm using this and it works well.
dir | Rename-Item -NewName { $_.Name -replace " - xx_xx","" }
However, there are other parts like:
" - yy_yy"
" - zz_zz"
What can I do to remove all of these at once instead of running it again and again changing the part of the name I want removed?

Answer 1

Easiest way
You can keep on stringing -replace statements until the cows come home, if you need to.
$myLongFileName = "Something xx_xx yy_yy zz_zz" -replace "xx_xx","" -replace "yy_yy"
More Terse Syntax
If every file has these, you can also make an array of pieces you want to replace, like this, just separating them with commas.
$stuffWeDontWantInOurFile =#("xx_xx", "yy_yy", "zz_zz")
$myLongFileName -replace $stuffWeDontWantInOurFile, ""
Yet another way
If your file elements are separated by spaces or dashes or something predictable, you can split the file name on that.
$myLongFileName = "Something xx_xx yy_yy zz_zz"
PS> $myLongFileName.Split()
Something
xx_xx
yy_yy
zz_zz
PS> $myLongFileName.Split()[0] #select just the first piece
Something
For spaces, you use the Spit() method with no overload inside of it.
If it were dashes or another character, you'd provide it like so Split("-"). Between these techniques, you should be able to do what you want to do.

Answer 2

If as you say, the pattern - xx_xx is always at the end of the file name, I'd suggest using something like this:
Get-ChildItem -Path '<TheFolderWhereTheFilesAre>' -File |
Rename-Item -NewName {
'{0}{1}' -f ($_.BaseName -replace '\s*-\s*.._..$'), $_.Extension
} -WhatIf
Remove the -WhatIf switch if you are satisfied with the results shown in the console
Result:
D:\Test\blah - xx_yy.txt --> D:\Test\blah.txt
D:\Test\somefile - zy_xa.txt --> D:\Test\somefile.txt
Regex details:
\s Match a single character that is a “whitespace character” (spaces, tabs, line breaks, etc.)
* Between zero and unlimited times, as many times as possible, giving back as needed (greedy)
- Match the character “-” literally
\s Match a single character that is a “whitespace character” (spaces, tabs, line breaks, etc.)
* Between zero and unlimited times, as many times as possible, giving back as needed (greedy)
. Match any single character that is not a line break character
. Match any single character that is not a line break character
_ Match the character “_” literally
. Match any single character that is not a line break character
. Match any single character that is not a line break character
$ Assert position at the end of the string (or before the line break at the end of the string, if any)