bash: How to change file extensions

This post shows how to change file extensions using bash.

To change file extensions, we simple need to loop through file in a directory and use the “mv” command to rename each file.

The following code requests directory address from the user and then renames all “.log” files to “.txt“

#!/bin/bash 
echo "Specify a directory: " 
read folder 
cd $folder 
for i in *.log     
    do     
    mv "$i" `basename $i log`txt 
done

Line 2 ask print the message “Specify a directory”.
Line 3 reads response from the user and stored it in the variable “folder”.
Line 4 take the control to that directory
Line 4-8 is the for loop that loop through all files with the extension “.log”.
Line 6 renames .log file to .txt