b4u - Usenet Binary File Transfer Tool

Usage:
  Send mode:    b4u -s -k <key> -n <newsgroups> -S <server:port> <file1> <file2> ...
  Receive mode: b4u -r -k <key> -n <newsgroups> -S <server:port>
  Save mode:    b4u -k <key> <file1> <file2> ...

Required Options:
  -k string        esub key password (required for all modes)
  -n string        Newsgroups (comma separated, required for send/receive)
  -S string        NNTP server:port (required for send/receive)

Mode Selection:
  -s               Send all files to newsgroup
  -r               Receive all files from specified newsgroup
  (no -s or -r)    Save articles locally without sending (creates 0001.txt, 0002.txt, etc.)

File Options:
  -b int           Block size in KB (default: 32, max: 256)
  -e               Mixmaster email mode (omits From: header)
  -f string        Custom From: header (default: Anonymous <anonymous@domain.tld>)
  -t string        To: address (for Mixmaster email mode)

NNTP Options:
  -tls             Use STARTTLS for encrypted connection
  -latest int      Download only last N articles (0 = all, default: 0)
  -batch int       Maximum batch size for XOVER command (default: 500)
  -timeout int     Read timeout in seconds (default: 1200)

Output Options:
  -v               Verbose output mode (shows progress and details)

Proxy Options:
  -pp int          SOCKS5 proxy port (0 = no proxy, default: 9050)

Cache & Resume Options:
  -rc              Enable replay cache and file cache
  -dbpath string   Custom path for cache JSON file

Behavior Notes:
  • Without -rc:        Downloads all articles from beginning
  • With -rc only:      Downloads all articles + saves state/cache
  • With -rc -latest N: Downloads only last N articles (ignores state)
  • State file:         <newsgroup>.json tracks last downloaded article

Examples:
  Send file:         b4u -s -k "my-password" -n alt.test -S news.server.com:119 file.zip
  Receive all:       b4u -r -k "my-password" -n alt.test -S news.server.com:119 -rc
  Last 250 articles: b4u -r -k "my-password" -n alt.test -S news.server.com:119 -latest 250
  Resume new only:   b4u -r -k "my-password" -n alt.test -S news.server.com:119 -rc
  Verbose output:    b4u -r -k "my-password" -n alt.test -S news.server.com:119 -v -rc
  No proxy:          b4u -r -k "my-password" -n alt.test -S news.server.com:119 -pp 0 -rc
  Large blocks:      b4u -s -k "my-password" -n alt.test -S news.server.com:119 -b 256 file.zip
  Custom From:  b4u -s -k "my-password" -n alt.test -S news.server.com:119 -f "John Doe <john@example.com>" file.zip