Open new Finder tab when using 'open .' in the Terminal
You cannot use open .
to open a new tab in Finder, though it is possible to open a new tab using AppleScript - from How do you duplicate current open Finder view in new tab (Mavericks)?
tell application "Finder"
activate
set t to target of Finder window 1
set toolbar visible of window 1 to true
end tell
tell application "System Events"
keystroke "t" using command down
end tell
tell application "Finder"
set target of Finder window 1 to t
end tell
Alternatively from http://macscripter.net/viewtopic.php?id=41624
set docs_path to (path to documents folder) as string
set Sat_folder to docs_path & "Sat:"
set ABC_folder to (Sat_folder & "ABC:") as alias
tell application "Finder"
activate
open Sat_folder
end tell
tell application "System Events" to keystroke "t" using command down
tell application "Finder"
set target of front window to ABC_folder
end tell
Probably a bit late, but in case other people are still searching for this.
In macOS Big Sur this works: System preferences > General > Prefer tabs > select always
from the dropdown menu.
Now open .
will open in a new tab in an existing Finder window. It also works from iTerm.