".com"で終わる文字列をテキストクリッピングファイルとして保存する方法が知りたい．

何度も済みません。ファイル名の先頭が「.」にならないための処理などいくつかの修正を加えました。

JavaScript

'use strict';

function grapheme_clusters(str) {
    const nsstr = $(str);
    const len = nsstr.length;
    let a = [];
    let i = 0;
    while (i < len) {
        const range = nsstr.rangeOfComposedCharacterSequenceAtIndex(i);
        a.push(nsstr.substringWithRange(range).js);
        i += Number(range.length);
    }
    return a;
}

function set_fname(str, ext) {
    const fsrep = $(str).fileSystemRepresentation.replace(/^\./, '_').replace(/[/:]/g, '_').replace(/\s+/g, ' ').trim();
    const margin = 5;
    let fname = '';
    if ((fsrep + ext).length < 256 - margin) {
        fname = fsrep;
    } else {
        const chrs = grapheme_clusters(fsrep);
        const ellipsis = '…';
        for (let i = 0; i < chrs.length; i++) {
            if ((fname + chrs[i] + ellipsis + ext).length > 255 - margin) {
                break;
            } else {
                fname += chrs[i];
            }
        }
        fname = fname + ellipsis;
    }
    return fname;
}

function resolve_conflicts(fpath, dname, fname, ext) {
    const filemanager = $.NSFileManager.defaultManager;
    let n = 2;
    while (filemanager.fileExistsAtPath($(fpath))) {
        fpath = `${dname}/${fname} ${n}${ext}`;
        if (n > 1000) {
            throw new Error(`${fpath}: filename: overflow`);
        }
        n++;
    }
    return fpath;
}

function run(argv) {
    if (argv.length < 1) {
        return 'usage: osascript -l JavaScript me.applescript string';
    }

    const query = argv[0].toString();

    const ext = '.textClipping';
    const fname = set_fname(query, ext);
    const dname = $('~/Desktop').stringByExpandingTildeInPath.js;

    let fpath = $(dname).stringByAppendingPathComponent(fname + ext).js;
    fpath = resolve_conflicts(fpath, dname, fname, ext);

    const furl = $.NSURL.fileURLWithPath(fpath);
    const dct = {'UTI-Data': {'public.utf8-plain-text': query}};
    const err = $();

    if (! $(dct).writeToURLError(furl, err)) {
        throw new Error(err.localizedDescription.js);
    }

    return [furl.path.js, query];
}