jsmv

Re-organize files with Javascript. Uses Deno. Download

Samples

Add the ".js" extension to all entries in a directory
jsmv exampledir 'f.mv(f + ".js")

Add the ".js" file extension to all files in a directory
jsmv exampledir 'if (f.isFile) f.mv(f + ".js")

Delete all backups and create new ones
jsmv src "f.endsWith('.backup') ? f.del() : f.mv(f + '.backup')"

Number files
jsmv src "f.mv(ctx.i++ + '.js')" --ctx "{i: 0}"

Look at the e2e tests for more examples.

How to Use

jsmv runs a Javascript snippet on every file/directory in a given directory.

The command format is jsmv dir_name snippet_or_file_name <FLAGS>

You can either provide a JS snippet or a file that contains a JS snippet.

The JS snippet has access to the variable f. By default f is described by the defaultFileObj class. It's well commented. There's also ctx which is a variable that is persistent between every execution of the snippet. It is possible to add/delete properties on ctx, but re-assignment is impossible.

Entry = The current file/directory being operated on.

The rough summary:

• Use del, mv, and cp to manipulate the current entry.
• Use instance variables like path, dirname, name, isDir, and isFile to get useful info.
• f extends String so f + ".js" will return "hello.js" if the current entry is "hello".

Helpers

jsmv currently has 1 helper: string_map under the h variable which is available to your function. Use like so in a snippet: "console.log(h.string_map('abc1def2ghi', /\d/, slice => (parseInt(slice) + 1) + 'Q'))" will print abc2Qdef3Qghi A useful tool if you want, e.g., increase the number in a file name by 1.

Warning: Probably has bugs.

--fileObj and JSMOVE_FILEOBJ_PATH

If you want f to have custom functionality you can implement your own "FileObj" class. See fileobj-examples.

JSMOVE_FILEOBJ_PATH is an optional environment variable to a file path with a custom FileObj class. --fileObj overrides JSMOVE_FILEOBJ_PATH.

--ctx and JSMOVE_CTX

--ctx is a snippet of JS-object-notation (e.g {foo: "bar"}) that will be executed to create the initial context. Without it, the initial context is empty.

JSMOVE_CTX operates similarly to JSMOVE_FILEOBJ_PATH except it's not a path.

Guidelines

All custom FileObj classes should implement the getOp operation. File system operations should not be done directly inside the FileObj class. Rather, an Op should be returned by getOp. This has several benefits:

• Atomicity (explained here)
• jsmv can do checks like
  • ensuring files are only deleted if -d is passed
  • ensuring moves don't overwrite files unless -o is passed

Order of Operations

Atomicity

Before any file system changes occur, jsmv will execute the JS snippet on all files/directories in the given directory and collect a list of operations to execute. This ensures changes are executed semi-atomically since if the JS snippet crashes, no file system changes will occur.

Deletes First

Deletes are done before moves/copies. This allows operations like "remove all files with the extension .backup and add the .backup extension to the remaining files" without accidentally deleting the newly created backups.