How can I use Regexp to rename files in Dired mode?

Question

I've have some videos (.mp4) with subtitles files (.SRT) that I need to rename. These files have long names so I can only rename them manually. I've tried Python to rename them, but it fails.

I've tried to rename it with Spacemacs and I did it using Dired SPC f j to open the folder and renamed the files going line by line: Select the line, go after the number of the video and then deleting till the dot of the extension, I created a simple macro that do this and then ran the macro on all the files in that folder.

I would like to do it with a regexp, so that I can also learn about it.

The folder looks like this in Dired:

total used in directory 477255 available 38636028
drwxrwxrwx  1 User None     28672 02-23 19:04 ..
drwxrwxrwx  1 User None      8192 02-23 19:02 .
-rw-rw-rw-  1 User None  30019832 02-23 13:13 010 Introduction to Global Economics.mp4
-rw-rw-rw-  1 User None      8514 02-23 13:13 010 Introduction to Global Economics-subtitle-en.srt
-rw-rw-rw-  1 User None    263198 02-23 13:13 011 BLS-Unemployment.pdf
-rw-rw-rw-  1 User None 108247504 02-23 13:13 011 The International Monetary Fund GDP.mp4
-rw-rw-rw-  1 User None     28101 02-23 13:14 011 The International Monetary Fund GDP-subtitle-en.srt
-rw-rw-rw-  1 User None  35996597 02-23 13:14 012 Excel Exercise 1 Analyzing IMF GDP Data.mp4
-rw-rw-rw-  1 User None     11454 02-23 12:17 012 Excel Exercise 1 Analyzing IMF GDP Data-subtitle-en.srt
-rw-rw-rw-  1 User None  37911096 02-23 13:15 012 Exercise-1.xlsx
-rw-rw-rw-  1 User None 104361394 02-23 13:15 013 Excel Exercise 1 Part 1 of 3.mp4
-rw-rw-rw-  1 User None     37892 02-23 13:11 013 Excel Exercise 1 Part 1 of 3-subtitle-en.srt
-rw-rw-rw-  1 User None  77650639 02-23 13:13 014 Excel Exercise 1 Part 2 of 3.mp4
-rw-rw-rw-  1 User None     32563 02-23 13:13 014 Excel Exercise 1 Part 2 of 3-subtitle-en.srt
-rw-rw-rw-  1 User None  94068512 02-23 13:14 015 Excel Exercise 1 Part 3 of 3.mp4
-rw-rw-rw-  1 User None     34325 02-23 13:14 015 Excel Exercise 1 Part 3 of 3-subtitle-en.srt

I want to rename the file: 010 Introduction to Global Economics.mp4 to 010.mp4 and 010 Introduction to Global Economics-subtitle-en.srt to 010.srt. Also, there are some other files that should not be renamed.

Till now, I tried this \b[0-9]\{3\}\b\( w*\)+.mp4 and it selects the .mp4 files, but how can I then tell it to keep the number of the video?

Edit: All the videos and subtitle files number have always 3 digits, from 001 to 252.

Answer 1

Found out, by trial and error that this works: \(\b[0-9]\{3\}\b\)\( w*\)*.*\(.mp4\|.srt\) and replace it by \1\3.

Answer 2

In spacemacs you can use the key combinations in the other comments, or you can do SPC SPC dired-toggle-read-only to enter edit mode. Once completed, you can use SPC SPC wdired-finish-edit to complete, or SPC SPC wdired-abort-changes to abort. Once in edit mode, you can used good'ol :%s/replace this/with this/gc kind of thing to rename your files.