Experimental Physics and
Industrial Control System

On Sep 29, 2019, at 8:25 PM, Michael Davidsaver via Tech-talk <[email protected]> wrote:

On 9/29/19 6:35 PM, Jemian, Pete R. via Tech-talk wrote:

Working in the IOC shell (EPICS base 7.0.3), how to remove the last 
character from an EPICS environment variable?

I don't think there is any way to do this at present.
The IOC shell isn't a fully featured shell/programming language.

given this definition:   epicsEnvSet(PREFIX, "xxx:")
I want to achieve this result: "xxx" by somehow editing $(PREFIX) in place.

In bash, this is possible using ${PREFIX::-1} but in the IOC shell:

iocxxx> echo $(PREFIX::-1)
macLib: macro PREFIX::-1 is undefined (expanding string echo $(PREFIX::-1))


The context is I want to change this line from:

dbLoadRecords("some.db","IOCNAME=$(PREFIX)")

to:

dbLoadRecords("some.db","IOCNAME=$(PREFIX - 1 character)")

I think you'll have to resort to doing this the other way around.

epicsEnvSet("IOCNAME", "blah")
epicsEnvSet("PREFIX", "$(IOCNAME):")