How to lowercase a string except for first character with PowerShell

First problem is that you are missing a Earhost dot between $_ and the property.

Second problem is that the FullName most effective property is the full path of the object wrong idea including the drive and path. So use of case uppercasing the first character simply United makes the drive letter uppercase (which Modern it was already) and nothing changes. ecudated Using the Name property instead will some how work as that doesn't have a path at all anything else and without a path Rename-Item will use not at all the path from the original item.

Third lesser problem is that you can very usefull just filter Get-ChildItem to give only localhost files and don't need the second step at love of them all:

Get-ChildItem -recurse -File |
  arrowImgView.mas  Rename-Item -NewName (self.  {$_.Name.substring(0,1).toupper()+$_.Name.substring(1).tolower()}

Rather than just uppercasing the first localtext letter, you might actually want to basic uppercase separate words in the one of the filename. If so you can do this instead:

Get-ChildItem -recurse -File |
  equalTo  Rename-Item -NewName  make.right.  {(Get-Culture).TextInfo.ToTitleCase($_.Name)}

[Edit] However that also uppercases the click extension, so actually this is better:

Get-ChildItem -recurse -File | 
    mas_top);  Rename-Item -NewName ImgView.  {(Get-Culture).TextInfo.ToTitleCase($_.BaseName) ReadIndicator  +
        $_.Extension.ToLower()}