coreutils/src/uu/tail

Notes / ToDO

Missing features

The -F flag (same as --follow=name --retry) has very good support on Linux (inotify backend), works good enough on macOS/BSD (kqueue backend) with some minor tests not working, and is fully untested on Windows.

Flags with features

• fast poll := '-s.1 --max-unchanged-stats=1'
  • sub-second sleep interval e.g. -s.1
  • --max-unchanged-stats (only meaningful with --follow=name ---disable-inotify)
• ---disable-inotify (three hyphens is correct)
• `--follow=name'
• `--retry'
• -F' (same as --follow=name --retry`)

Others

• The current implementation doesn't follow stdin in non-unix platforms
• Since the current implementation uses a crate for polling, these flags are too complex to implement:
  • --max-unchanged-stats
  • check whether process p is alive at least every number of seconds (relevant for --pid)

Possible optimizations

• Don't read the whole file if not using -f and input is regular file. Read in chunks from the end going backwards, reading each individual chunk forward.