Replace or delete certain characters from filenames of all files in a folder [closed]

Use PowerShell to do anything smarter for a DOS prompt. Here, I’ve shown how to batch rename all the files and directories in the current directory that contain spaces by replacing them with _ underscores.

Dir |
Rename-Item -NewName { $_.Name -replace " ","_" }

EDIT :
Optionally, the Where-Object command can be used to filter out ineligible objects for the successive cmdlet (command-let). The following are some examples to illustrate the flexibility it can afford you:

• To skip any document files

  Dir |
  Where-Object { $_.Name -notmatch "\.(doc|xls|ppt)x?$" } |
  Rename-Item -NewName { $_.Name -replace " ","_" }
  

• To process only directories (pre-3.0 version)

  Dir |
  Where-Object { $_.Mode -match "^d" } |
  Rename-Item -NewName { $_.Name -replace " ","_" }
  

  PowerShell v3.0 introduced new Dir flags. You can also use Dir -Directory there.

• To skip any files already containing an underscore (or some other character)

  Dir |
  Where-Object { -not $_.Name.Contains("_") } |
  Rename-Item -NewName { $_.Name -replace " ","_" }