https://www.ciscolive.com/c/dam/r/ciscolive/emea/docs/2020/pdf/LTRARC-2002.pdf

• In principle, commit in every level of configuration you add.

show configuration commit changes diff
show configuration commit list
show configuration commit changes last 1
rollback configuration last 1
show run | utility ?    # This for a lot of unix utilities 
pwd    # to see where I am in the hierarchy of commands
abort   # to abort the changes we just made (before the commit

In a lab environment do this to prevent constant logouts:

line console session-timeout 35000
line console exec-timeout 35000
line console absolute-timeout 10000
commit

This is for bgp (note address-family ipv4 unicast is needed after each neighbor (and commit) for it to work: router bgp 20000

 bgp router-id 10.255.255.20
 address-family ipv4 unicast
  network 10.255.255.20/32
 !
 neighbor 10.255.255.20
  remote-as 20000
  update-source Loopback0
  address-family ipv4 unicast
  !
 !
 neighbor 10.255.255.21
  remote-as 20000
  update-source Loopback0
  address-family ipv4 unicast
  !
 !
 
* There is not ''| s'' or pipe section. If we want to see sectios of the configuration we do things like:
show configuration router bgp