wezterm/docs/config/lua/pane/get_foreground_process_name.md

pane:get_foreground_process_name()

Since: nightly builds only

Returns the path to the executable image for the pane.

This method has some restrictions and caveats:

• This information is only available for local panes. Multiplexer panes do not report this information. Similarly, if you are using eg: ssh to connect to a remote host, you won't be able to access the name of the remote process that is running.
• On unix systems, the process group leader (the foreground process) will be queried, but that concept doesn't exist on Windows, so instead, the process tree of the originally spawned program is examined, and the most recently spawned descendant is assumed to be the foreground process
• On Linux, macOS and Windows, the process can be queried to determine this path. Other operating systems (notably, FreeBSD and other unix systems) are not currently supported
• Querying the path may fail for a variety of reasons outside of the control of WezTerm
• Querying process information has some runtime overhead, which may cause wezterm to slow down if over-used.

If the path is not known then this method returns nil.

This example sets the right status are to the executable path:

local wezterm = require 'wezterm'

-- Equivalent to POSIX basename(3)
-- Given "/foo/bar" returns "bar"
-- Given "c:\\foo\\bar" returns "bar"
function basename(s)
  return string.gsub(s, "(.*[/\\])(.*)", "%2")
end

wezterm.on("update-right-status", function(window, pane)
  window:set_right_status(basename(pane:get_foreground_process_name()))
end)

return {
}