Issue
I have a sequence of folders containing mp4 files (one mp4 in one folder). Folders are numbered sequentially like this example:
.. ..
18. Lesson 18 - Sketching a design to cut out
19. Lesson 19 - How to create a sweep
.. ..
the .mp4 files inside these folders are named, respectively:
.. ..
1. Sketching a design to cut out.mp4
1. Creating a sweep.mp4
.. ...
So all .mp4 file names start with "1." regardless of the folder name. I want to rename all mp4 files with an ascending prefix taken from the folder number, i.e.
18. Sketching a design to cut out.mp4
19. Creating a sweep.mp4
.. ..
for this I want to use the following bash script:
for f in *.mp4; do mv "$f" "$(echo "$f" | sed s/1./MYNUMBER/)"; done
How to specify a sequential prefix taken from folder names instead of 'MYNUMBER'? Folder names and filenames both include whitespace. Possibly, there is another way though.
Solution
Using Perl's rename (usable in any OS):
Hierarchy:
tree
.
├── 18. Lesson 18 - Sketching a design to cut out
│ └── 1. Sketching a design to cut out.mp4
└── 19. Lesson 19 - How to create a sweep
└── 1. Creating a sweep.mp4
2 directories, 2 files
Code:
rename -n 's@\./(\d+\.)[^/]+/\d+\.\s*(.*)@$1 $2@' ./*/*.mp4
rmdir *
ls -1
Output:
'18. Sketching a design to cut out.mp4'
'19. Creating a sweep.mp4'
The regular expression matches as follows:
| Node | Explanation |
|---|---|
( |
group and capture to \1: |
\d+ |
digits (0-9) (1 or more times (matching the most amount possible)) |
\. |
. |
) |
end of \1 |
[^/]+ |
any character except: / (1 or more times (matching the most amount possible)) |
/ |
/ |
\d+ |
digits (0-9) (1 or more times (matching the most amount possible)) |
\. |
. |
\s* |
whitespace (\n, \r, \t, \f, and " ") (0 or more times (matching the most amount possible)) |
( |
group and capture to \2: |
.* |
any character except \n (0 or more times (matching the most amount possible)) |
) |
end of \2 |
Answered By - Gilles Quénot Answer Checked By - Gilberto Lyons (WPSolving Admin)