benchmark_shuf.sh

# creat a test file
$time seq 1 10000000 > ten_million.txt
seq 1 10000000 > ten_million.txt  3.51s user 0.13s system 99% cpu 3.663 total

# it is a "big" file with size of 109M
$ls -lh ten_million.txt 
-rw-r--r--  1 Tammy  staff   109M Mar 22 20:49 ten_million.txt

$man gshuf
# randomly select 1000 lines from it
$time gshuf -n 1000 ten_million.txt > /dev/null
gshuf -n 1000 ten_million.txt > /dev/null  0.79s user 0.03s system 96% cpu 0.853 total

# after git clone the fast_sample, make a soft link of the executable to /usr/local/bin
# so that I can invoke it anywhere
git clone https://github.com/earino/fast_sample
ln -s /Users/Tammy/github_repos/fast_sample/fast_sample /usr/local/bin

$time  fast_sample -n 1000 ten_million.txt > /dev/null
fast_sample -n 1000 ten_million.txt > /dev/null  4.70s user 0.04s system 99% cpu 4.770 total