This program was inspired by its namesake, the line-counting functionality in the ubiquitous 'wc' application found on most UNIX systems.
wcf provides fuzzy line-count estimates that can instantaneously provide results and, optionally, continue refining the estimate while you wait.
The f in wcf stands a little bit for fast, but mostly it stands for fuzzy :p.
arman@arman-desktop:~$ wcf --help
fast and fuzzy line counts, with optional best-guesses while you wait:
-h [ --help ] Display this help screen
-f [ --file ] arg Input file to count lines from
-l [ --live ] Update the best guess after each interval,
and return when the actual line count is
known. This overrides default behavior,
where wcf simply returns after the first
interval with the line count guess
-s [ --simple-output ] Output only the guess value without
accuracy estimation. If live mode is
disabled this will cause wcf to only
output the guess value once
-t [ --time-interval ] arg (=0.25) Time in seconds between line count
updates. Set to 0 to only display the line
count once the whole file has been read.