How do I change the extension of many files in a directory?

Question

Suppose I have a large number of files in a directory with .txt extension.

How can I change the extension of all these files to .c using the following command line environments:

• Powershell in Windows
• cmd/DOS in Windows
• The terminal in bash

Solution

On Windows, go to the desired directory, and type:

ren *.txt *.c

In PowerShell, it is better to use the Path.ChangeExtension method instead of -replace (thanks to Ohad Schneider for the remark):

Dir *.txt | rename-item -newname { [io.path]::ChangeExtension($_.name, "c") }

For Linux (Bash):

for file in *.txt
do
 mv "$file" "${file%.txt}.c"
done

Comments

[Timo]

Does the % in Bash work like a separator to end the string? like $ in regex?

[fartwhif]

Dir -Recurse for recursive search