Use FIND with MV to rename files. Delete the found string then prepending it to the filename?

Question

find . -type f -name '*authors-name-string*' -exec bash -c 'mv "$0" "${0/authors-name-string/}"' {} \;

I am trying to rename files nested in several layers of directories that contain an author's name text string embedded somewhat randomly in the filename. Creating a new filename that starts with the author's name followed by the rest of the original filename ... but sans the authors name string that was located in a somewhat random location in the original filename.

The shell command line above will recursively remove the authors-name-text string from the filename, but I have not figured out how to do that AND prepend the authors-name-text (and a trailing "_" underscore) to the start of the filename. Basically I want to move the authors-name-text from wherever it is currently in the filename to being at the beginning of the filename (plus an underscore). As far as I can tell the bash version invoked is v4.3 on my Synology NAS. I've logged in via ssh from my MacBook.

Trying to take thousands of files in different directories organized by subject directory name so that some of the files written by the same author inside the directories appear grouped together when viewing a simple directory listing.

find . -type f -name '*authors-name-string*' -exec bash -c 'mv "$0" "authors-name-string_${0/authors-name-string/}"' {} \;

The above command line fails when it tries to insert the "authors-name-string_" at the front of the entire filename pathway. Since there isn't a starting directory by that name the MV command complains, though, it does still remove the author-name-string from it's original location in the filename as desired.

Answer 1

Expanding on your approach and leveraging parameter expansion:

export author_string='author1'
export new_string='author1'
find . -type f -name "*${author_string}*" \
  -exec sh -c '
    path="${1%/*}"
    tmp="${1%%${author_string}[^/]*}"
    before="${tmp##*/}"
    after="${1##*${author_string}}"
    echo mv -- "$1" "${path}/${new_string}_${before}${after}"' sh {} \;

My assumptions, since I'm not sure I completely understand your question:

You are searching for files whose name contains a fixed string; here, the variable author_string.
You are renaming files everywhere in a directory tree.
The new name of your files will start with a fixed string (it being the same as author_string or not, makes no big difference); here, the variable new_string.
The remainder of the new name of your files will be equal to their old name, except for the author_string part, which you want removed.

In this code:

• We export our old/new strings to make them available to the shell invoked by find.

• With an eye on portability, -exec calls sh. $1 is used instead of $0, as in your snippets, because $0 is typically used to set the name of the shell/command.

• For each file, we split its full path:

  • path="${1%/*}" is the full path with the file name part removed: ${parameter%word} removes a suffix that matches the word pattern;

  • tmp="${1%%${author_string}[^/]*}" catches the part of each file's full path that precedes author_string: ${parameter%%word} removes the longest suffix that matches the word pattern. We use [^/] to ignore any occurrence of author_string as part of directory names;

  • before="${tmp##*/}" captures only the substring that is part of the file name: ${parameter##word} removes the longest prefix that matches the word pattern;

  • after="${1##*${author_string}}" is the part of the file name that comes after author_string;

• We rename each file.

Note that, if author_string is repeated in a file name, anything in between the occurrences is lost.

Also, bear in mind that you will need to escape (with a \) all the characters in author_string that have a special pattern matching meaning, if you want to match them literally.

Given the directory tree:

$ tree .
.
├── testdir
│   ├── title2_author1_date.book
│   ├── title3_author1_date.book
│   └── title4_author2_date.book
├── title1_author1_date.book
└── title5_author2_date.book

This code does:

$ export author_string='author1' new_string='author1'; find . -type f -name "*${author_string}*" -exec sh -c 'path="${1%/*}"; tmp="${1%%${author_string}[^/]*}"; before="${tmp##*/}"; after="${1##*${author_string}}"; echo mv -- "$1" "${path}/${new_string}_${before}${after}"' sh {} \;
mv -- ./title1_author1_date.book ./author1_title1__date.book
mv -- ./testdir/title3_author1_date.book ./testdir/author1_title3__date.book
mv -- ./testdir/title2_author1_date.book ./testdir/author1_title2__date.book

Remove echo from the command when you feel you are ready to actually rename files.

---

References:

Parameter Expansion in "The Open Group Base Specifications Issue 7, 2018 edition" (POSIX.1-2017)

Answer 2

Sounds like a job for Larry Wall's rename. Beware there are other commands with the same name, this one is written in purl.