Add file extension to files with bash

Question

What is the good way to add file extension \".jpg\" to extension-less files with bash?

Answer 1

for f in *.jpg; do mv "$f" "${f%.jpg}"; done
for f in *; do mv "$f" "$f.jpg"; done

Answer 2

You can use move multiple files. I am a maintainer of this project. The syntax is simple.

mmf files*

It will open your $EDITOR with all files names, or vim by default and you can simply highlight the end of all file names using Ctrl+v+G in vim , save the file,quit and that it , all your files are renamed

Answer 3

Ryan Li

The correct syntax for adding a file extension to multiple files within a directory which do not have a file extension is

find . | while read FILE; do if [[ -n `file --mime-type "$FILE" | grep 'message/rfc822'` ]]; then  mv "$FILE" "$FILE".eml; fi; done;

Answer 4

In my case i was not aware of the filetype so i used the mv command with the help of the file command to examine and possibly find the file type. This solution might not be perfect for all files since the file command might not recognize the filetype but it worked mostly good for me.

for f in *; do ext=$(file $f | awk '{print $2;}'); mv -n "$f" "$f.$ext"; done

The use of awk is to strip the second word of the string returned from the command file that is actually the extension.