I wrote some triggers to get colors when using iTerm2 (screenshot below) with Arista EOS but it should also work on Cisco IOSes with some minor tuning.
iTerm2 is a replacement for Terminal and the successor to iTerm. It works on Macs with macOS 10.14 or newer. It allows you to create Triggers. Triggers watch for text matching a regular expression to arrive in a terminal session and then perform an action in response. You can't import triggers from a file/profile but you can configure them on "Preferences, Profile, Advanced, Edit Triggers".
( up\s+up ) | connected Highlight text in green. ( down (down|lowerlayerdown|notpresent) )| notconnect | errdisabledHighlight text in red.
BGP sessions status
( Estab ) | Established Highlight text in green when bgp session is established. Estab +\d+ +0 Highlight text in orange when bgp session is established and no route is received. .*\s(Active|Idle\(NoIf\)|Idle\(MaxPath\)|Connect|Passive)\s*$ Highlight all the line in red when bgp session is not established.
If you are using observium syntax...
\sCore: Highlight text in violet. \sCust: Highlight text in blue. \sServer: Highlight text in green.
Set colors on logs lines/patterns
.* %LINEPROTO-5-UPDOWN: .* down
.* %LINEPROTO-5-UPDOWN: .* up