Mac OSX

sudo ln /usr/local/* /usr/lib/** , Operation not permitted.

This is because EI Capitan has a protection mode. Only /usr/local is open permitted to operation. Other folder is in protection. We can
-- Reboot mac and keep press cmd+r when booting up
-- Then go to Utilities > Terminal
-- Type following commands

csrutil disable
reboot

Show hidden files

defaults write com.apple.finder AppleShowAllFiles YES

killall Finder

then, option + right click, relaunch

Show command duration

time ls -alr

output

real	0m0.033s
user	0m0.002s
sys	0m0.004s

Fix: OSX 10.12.4~6 sudo hangs so long before entering password

Universal Workaround step by step:

1. open terminal.app (or Iterm)

2. sudo visudo

3. wait until entering your password

4. navigate to each line starting with a '%' sign (those are group definitions)

5. press 'i' followed by '#' followed by the Escape key. (place a '#' in front of this line)

6. repeat step 5 for every line starting with a % sign.

8. start a new line (I recommend one near the group definitions) and enter `jone  ALL=(ALL) ALL`, 'jone' represents your username.

10. press ESC and typing ':wq' and press enter.

Get your user name

id -u -nr