How to rename files to specific string in their filenames
I have large amount of .json files that need to be renamed to a specific string of numbers in each file’s name. They follow the format:
[Artist] Title (Date) [Language][Publisher][Website.####][Pages].json
"####" represents a unique numerical ID which I need to rename each file to, ranging from 1-4 characters long. It should look like this:
####.json
How can I achieve this?
With zsh:
autoload -Uz zmv
zmv -n '*[*.(<->)][*(.json)' '$1$2'
Remove the -n (dry-run) if happy.
The zmv autoloadable function takes two arguments:
- a zsh extended glob pattern
- a replacement specification
It finds the files that match the pattern, here all the non-hidden ones in the current directory that contain in sequence:
*any number of characters (or bytes)[a literal[*any number of characters (or bytes).a literal.<->any sequence of ASCII decimal digit (<x-y>matches on sequences of ASCII decimal digits representing numbers from x to y)][:][literally.*any number of characters (or bytes).json: literally.
In the replacement, $1 expands to what was matched inside the first pair of (...), so the number matched by <-> and $2 to the second (.json).
Note that as those * match greedly, it will find that number in the rightmost pair of [...] whose contents ends in .<digits> (excluding the last). For instance in [a.1][a.2.3][x][y][z].json, it will extract 3 even though that’s not in the second-last pair of [...]s.
If that’s a problem, you can change it to:
zmv -n '*.(<->)][[^][]#](.json)' '$1$2'
Where [^][]# matches on 0 or more characters (or non-characters) other than [ and ].