tramp-echo-mark

tramp-echo-mark is a variable defined in `tramp.el'.
Its value is

"_echo"

• This variable may be risky if used as a file-local variable.

Documentation:
String mark to be transmitted around shell commands.
Used to separate their echo from the output they produce. This
will only be used if we cannot disable remote echo via stty.
This string must have no effect on the remote shell except for
producing some echo which can later be detected by
`tramp-echoed-echo-mark-regexp'. Using `tramp-echo-mark-marker',
followed by an equal number of backspaces to erase them will
usually suffice.