No bench update --bench

I was installed the bench and erpnext using the easyinstall script…
Now I need to update the bench cli command to get it’s latest options…
How should I do it ??

s@erpnext:~/bench$ bench --version
s@erpnext:~/bench$ pip  list | grep bench
bench               5.0.0               /home/s/.bench
s@erpnext:~/bench$ whereis bench
bench: /usr/local/bin/bench
s@erpnext:~/bench$bench update --help
Usage: bench update [OPTIONS]

  Updates bench tool and if executed in a bench directory, without any flags
  will backup, pull, setup requirements, build, run patches and restart
  bench. Using specific flags will only do certain tasks instead of all

  --pull                Pull updates for all the apps in bench
  --patch               Run migrations for all sites in the bench
  --build               Build JS and CSS assets for the bench
  --requirements        Update requirements. If run alone, equivalent to
                        `bench setup requirements`
  --restart-supervisor  Restart supervisor processes after update
  --restart-systemd     Restart systemd units after update
  --no-backup           If this flag is set, sites won't be backed up prior to
                        updates. Note: This is not recommended in production.
  --force               Forces major version upgrades
  --reset               Hard resets git branch's to their new states
                        overriding any changes and overriding rebase on pull
  --help                Show this message and exit.

the Install script clones the master branch of bench by default. You can uninstall this if you wish to and install it directly from PyPI, else just use this as is. You should probably review the changes before you update the bench tool.