Molt: batch renaming utility

Question

Hi all,
Recently I was looking for a batch renaming utility, and while I did find a few, none of them would really fill all the checkboxes of my requirements list. Either because they didn’t provide the "rules" I was looking for, or because they would rename files after each rule has been applied, or because they couldn’t be used from scripts (that way I wanted), or whatever the reason. So I made myself one: molt.
You use it by specifying a set of rules to use, which will all be processed to determine the new name. molt will make sure those new names are "free," as in not already in use; and handles "avoidable conflicts" - when a file's new name is taken by another file to be renamed (performing two-steps renaming with a temporary name if needed).
Usage: molt [OPTION]... RULE... [FILE]...
Options :
-D, --exclude-directories Ignore directories from specified files
-F, --exclude-files Ignore files from specified files
-S, --exclude-symlinks Ignore symlinks from specified files
-i, --from-stdin Get list of files from stdin
-P, --process-fullname Send the full path/name to the rules
(Imply --output-fullname)
-p, --allow-path Allow (relative/absolute) paths in new filenames
(Imply --output-fullname)
-m, --make-parents Create parents if needed
-O, --output-fullname Output full path/names
-B, --output-both-names Output the old then the new filename for each file
-N, --output-new-names Output the new filename for each file
-R, --only-rules Only apply the rules and output results,
without any conflict detection
(Imply --dry-run)
-n, --dry-run Do not rename anything
-C, --continue-on-error Process as much as possible, even on errors
or when conflicts are detected
-d, --debug Enable debug mode - Specify twice for verbose
output
-h, --help Show this help screen and exit - Specify twice for
verbose output
-V, --version Show version information and exit
Rules :
Rules are the part of molt that process filenames. Rules will be applied
in the order specified, you can use the same rule as may times as you want.
Some rules require a parameter, what it can be depend of the rule. Usually,
it will be a string where you can specify multiple parameter using slash ( / )
as separator.
--upper Convert to uppercase
--lower Convert to lowercase
--vars Resolve variables
--tpl PARAM Apply specified template (resolve variables)
--sr PARAM Search & replace a string
PARAM = search[/replacement[/option]]
If no replacement is specified, the string will be removed.
Search is case-sensitive, unless option i was specified.
--camel Convert to Camel Case
--list Use list of new names from stdin
--regex PARAM Search & replace using regular expression
PARAM = pattern[/replacement[/option]]
If no replacement is specified, the string will be removed.
Search is case-sensitive, unless option i was specified.
Variables :
You can use variables in the new filenames. The syntax is to put the
variable's name in between dollar signs, e.g: $FOOBAR$
You can also (if supported) specify one (or more) parameters, using colon
as separator, e.g: $FOOBAR:PARAM1:PARAM2$
Variables are not automatically resolved, you need to use the rule --vars
in order to have them resolved, which gives you the ability to determine
when resolving happens, and continue processing with more rules afterwards.
Note that rule --tpl also resolves variables.
NB[:PARAM...] Counter, incremented for each file using it
You can specify up to 3 parameters:
- the minimum number number of digits (padding with 0's)
- the starting value of the counter
- the increment (can be negative)
E.g: $NB:3:42:-2$ will resolve as 042, 040, 038, etc
_[:PARAM...] Magic variable: specify "variable" as parameter
The first parameter is the name of the "variable" to resolve.
Resolving is done running the corresponding command line, using output
as value (removing trailing newline (\n) if present)
Links:
- Slightly more verbose description
- Source code
- PKGBUILD in the AUR
Hopefully someone may find it useful.
Cheers,
-jacky

Answer 1

Yes, this works. However, this was already part of my workflow.... and not where the trouble lies.
After exporting jpeg images from Aperture, they carry the same name of the original RAW files, from which they came. (So, IMG_8342.jpg would have started it's life as IMG_8342.CR2.) But we dont' send them out like that. We sequentially name them 0001_image.jpg, 0002_image.jpg, etc... So after renaming, how do you find the original file again, right?
BEFORE the renaming phase, I would run the "Store Original Names in Spotlight Comments" action. That way, I could look at the comments for a derivative .jpg—whose name has now changed—and determine the name of the ORIGINAL file.
After renaming, the derivative file might end up being named 0361_image.jpg, but it's Spotlight comments would say, for example, Original Name:<<IMG_8485.jpg>>. Then I would know that this particular file started off as IMG_8485.CR2.
As such, I could quickly/easily backtrack, knowing that the original RAW file was named IMG_8485.CR2
The issue is that once you've gone thru the effort to ADD these spotlight comments, if you THEN go through a re-naming step, this erases all those Spotlight Comments. That was my problem... Getting the Spotlight Comments in place was never the issue. KEEPING them there was the problem.