helper utility for saving a Markdown file

'save' can be used to save a Markdown file, with optional frontmatter
and additional tags. By default, if set, `FABRIC_FRONTMATTER_TAGS` will
be placed into the file as it is written. These tags and front matter
are suppressed from STDOUT, which can be piped into other patterns or
programs with no ill effects. This strives to be a version of `tee` that
is enhanced for personal knowledge systems that use frontmatter.

helpers/save

@@ -0,0 +1,109 @@
+#!/usr/bin/env python3
+import argparse
+import os
+import sys
+from datetime import datetime
+
+from dotenv import load_dotenv
+
+DEFAULT_CONFIG = "~/.config/fabric/.env"
+PATH_KEY = "FABRIC_OUTPUT_PATH"
+FM_KEY = "FABRIC_FRONTMATTER_TAGS"
+DATE_FORMAT = "%Y-%m-%d"
+load_dotenv(os.path.expanduser(DEFAULT_CONFIG))
+
+
+def main(tag, tags, fabric):
+    out = os.getenv(PATH_KEY)
+    if out is None:
+        print(f"'{PATH_KEY}' not set in {DEFAULT_CONFIG} or in your environment.")
+        sys.exit(1)
+
+    out = os.path.expanduser(out)
+
+    if not os.path.isdir(out):
+        print(f"'{out}' does not exist. Create it and try again.")
+        sys.exit(1)
+
+    if not out.endswith("/"):
+        out += "/"
+
+    if len(sys.argv) < 2:
+        print(f"'{sys.argv[0]}' takes a single argument to tag your summary")
+        sys.exit(1)
+
+    yyyymmdd = datetime.now().strftime(DATE_FORMAT)
+    target = f"{out}{yyyymmdd}-{tag}.md"
+
+    # don't clobber existing files- add an incremented number to the end instead
+    would_clobber = True
+    inc = 0
+    while would_clobber:
+        if inc > 0:
+            target = f"{out}{yyyymmdd}-{tag}-{inc}.md"
+        if os.path.exists(target):
+            inc += 1
+        else:
+            would_clobber = False
+
+    # YAML frontmatter stubs for things like Obsidian
+    # Prevent a NoneType ending up in the tags
+    frontmatter_tags = ""
+    if fabric:
+        frontmatter_tags = os.getenv(FM_KEY)
+
+    with open(target, "w") as fp:
+        if frontmatter_tags or len(tags) != 0:
+            fp.write("---\n")
+            now = datetime.now().strftime(f"{DATE_FORMAT} %H:%M")
+            fp.write(f"generation_date: {now}\n")
+            fp.write(f"tags: {frontmatter_tags} {tag} {' '.join(tags)}\n")
+            fp.write("---\n")
+
+        # function like 'tee' and split the output to a file and STDOUT
+        for line in sys.stdin:
+            print(line, end="")
+            fp.write(line)
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(
+        description=(
+            'save: a "tee-like" utility to pipeline saving of content, '
+            "while keeping the output stream intact. Can optionally generate "
+            '"frontmatter" for PKM utilities like Obsidian via the '
+            '"FABRIC_FRONTMATTER" environment variable'
+        )
+    )
+    parser.add_argument(
+        "stub",
+        nargs="?",
+        help=(
+            "stub to describe your content. Use quotes if you have spaces. "
+            "Resulting format is YYYY-MM-DD-stub.md by default"
+        ),
+    )
+    parser.add_argument(
+        "-t,",
+        "--tag",
+        required=False,
+        action="append",
+        default=[],
+        help=(
+            "add an additional frontmatter tag. Use this argument multiple times"
+            "for  multiple tags"
+        ),
+    )
+    parser.add_argument(
+        "-n",
+        "--nofabric",
+        required=False,
+        action="store_false",
+        help="don't use the fabric tags, only use tags from --tag",
+    )
+    args = parser.parse_args()
+
+    if args.stub:
+        main(args.stub, args.tag, args.nofabric)
+    else:
+        parser.print_help()