backtick id lifespan autorefresh cmd args…
Program the backtick command with the numerical id id. The output of
such a command is used for substitution of the
%` string escape. The specified lifespan is the number of
seconds the output is considered valid. After this time, the command is
run again if a corresponding string escape is encountered. The
autorefresh parameter triggers an automatic refresh for caption and
hardstatus strings after the specified number of seconds. Only the last
line of output is used for substitution.
If both the lifespan and the autorefresh parameters are zero, the
backtick program is expected to stay in the background and generate output
once in a while. In this case, the command is executed right away and
screen stores the last line of output. If a new line gets printed,
screen will automatically refresh the hardstatus or the captions.
The second form of the command deletes the backtick command with the numerical id id.