This page is part of the ING document
manual for UltraDAS
command line and the observing commands
This section introduces commands that may be given at the SYS> prompt.
The interpreter for those commands is a Unix shell.
Commands by category
UltraDAS has a suite of commands that each do one observation:
Each of these operates the camera to make the observation, collates FITS-header
data from around the observing system and saves the observation in one
FITS-file. Run, arc, flat
and sky do the same observation,
but they are separate commands because they each record a different type
of observation in the FITS header (at the OBSTYPE keyword). Please
try to use the correct command for the exposure type: it makes the archived
observations more valuable to the community.
run for a science observation;
arc for an arc-lamp frame (but
not for a flat-field done with a lamp);
bias for a bias frame;
dark for a dark frame;
flash for a preflash-only frame
(this for engineering purposes, not for astronomy);
flat for a flat field (dome
flat, lamp flat or sky flat);
sky for a sky-background frame
(e.g. to measure fringes, but not for a sky flat-field).
For each single-observation commands there is a multiple-observation
equivalent: multrun, multarc,
Each of these does a series of similar observations. UltraDAS optimizes
the series by starting each observation as soon as the previous one has
read out. Hence, the multiple-exposure commands typically have two runs
in progress at a time.
The command glance makes an observation
but holds it in memory and does not record it on disc. This command is
sometimes useful with the automatic image-display
to check targeting and exposure level without wasting disc space.
The command scratch takes an observation
in the same manner as run and records it in a scratch
file. The commands is useful for building scripts that need to operate
on an observation in a known place.
You can create an archiveable file from
a glance observation using the keep command.
You can do the same for a scratch file using the promote
The command rspeed changes the readout
speed. There are two choices, called "fast " and "slow". There is no way
to change the clear speed of the camera.
The bin command sets binning factors in
the x and y directions. Set the factors factors back to 1,
1 with the same command to turn binning off.
Readout windows are supported. See the separate page on windowing.
You may also need to see the section on coordinate
There are three commands that affect observations which are already
Finish and newtime have no effect if an integration is not
in progress. Further, they do not affect cycles of a multrun that
have not yet begun.
abort stops an observation dead and
throws away the data.
finish truncates an integration
and makes the camera go on to read out the observation and store it normally.
newtime changes the request length
of an integration.
If you try to retime an observation to less time than it has already
integrated, newtime behaves like finish.
Exploiting the command shell
UltraDAS commands run from the shell in the same way as normal Unix commands
like ls: they are sub-processes of the shell. This means that they
can be manipulated using the normal Unix techniques.
You can freely mix observing commands with Unix commands like ls, cp,
mv lp etc.
Commands can be aborted using Cntrl-C and the Unix kill command.
Commands can be started in the background by typing an ampersand on the
end of the command.
A foreground command (one that is tying up the terminal) can be pushed
into the background by typing Cntrl-Z followed by the bg
command. (The bg part is important: if you omit this, the command
is left hung and never completes).
Commands show up as processes in the output of ps.
Commands set the shell variable status to zero if they success and
non-zero if they fail; script writers are encouraged to use this feature.
A semicolon between commands typed on the same line executes the commands
compmirror in ; complamps CuNe ; arc 3
is a sequence for IDS that takes and arc frame when the instrument is ready.
The construct "&&" between commands executes the second command
only when and if the first one completes successfully. This is the conditional
version of the arc-taking sequence:
compmirror in && complamps CuNe && arc 3
which doesn't take the arc if the instrument fails.
The construct "||" between commands executes the second command only if
the first fails. It's hard to see a use for this in the context of UltraDAS
run 5000 || echo "Argh! Noooooooooooo!!!!!!!!!!!!!!!!!"
The shell has a built-in repeat command:
repeat 10 run 30
is very nearly the same as
multrun 10 30
(the multrun is slightly quicker)