IOC Shell Library

Table of contents

• Environment and Function Lookup
  • iocsh.<item>

The iocsh library provides access to EPICS environment variables and iocsh-registered functions from Lua. In the Lua shell, this functionality is embedded into the global environment automatically – you can reference environment variables and iocsh functions by name without loading the library explicitly.

local iocsh = require("iocsh")

Environment and Function Lookup

iocsh.<item>

---

Look up an environment variable or iocsh function by name.

iocsh.<item> [(arguments)]

First checks for an EPICS environment variable matching the name. If none is found, searches for a registered iocsh function. Returns nil if neither is found.

-- Access an environment variable
local arch = iocsh.EPICS_HOST_ARCH

-- Call an iocsh function
iocsh.dbLoadRecords("my.db", "P=test:")

-- In the Lua shell, the iocsh prefix is optional:
EPICS_HOST_ARCH
dbLoadRecords("my.db", "P=test:")

When using the Lua shell, iocsh lookups are built into the global environment. Any name that isn’t a Lua variable is automatically checked as an environment variable or iocsh function. The explicit iocsh. prefix is only needed when using require("iocsh") in scripts outside the shell.

Parameter	Type	Description
item	string	The name of an environment variable or iocsh function.
arguments	varies	If referencing an iocsh function, the arguments to pass to it.

Returns: the environment variable value (as a string), the iocsh function reference, or nil if not found.