Ubuntu Manpage: halcmd - manipulate the LinuxCNC HAL from the command line

Provided by: linuxcnc-uspace_2.9.1-2ubuntu1_amd64

NAME

       halcmd - manipulate the LinuxCNC HAL from the command line

SYNOPSIS

       halcmd [OPTIONS] [COMMAND [ARG]]

DESCRIPTION

       halcmd  is  used to manipulate the HAL (Hardware Abstraction Layer) from the command line.
       halcmd can optionally read commands from a file, allowing complex HAL configurations to be
       set up with a single command.

       If  the  readline  library  is  available  when  LinuxCNC  is compiled, then halcmd offers
       commandline editing and completion when running interactively.  Use the up arrow to recall
       previous commands, and press tab to complete the names of items such as pins and signals.

OPTIONS

-I Before tearing down the realtime environment, run an interactive halcmd. halrun
only. If -I is used, it must precede all other commandline arguments.

-f [<file>]
Ignore commands on command line, take input from file instead. If file is not
specified, take input from stdin.

-i <INI file>
Use variables from the specified INI file for substitutions. See SUBSTITUTION
below.

-k Keep going after failed command(s). The default is to stop and return failure if
any command fails.

-q display errors only (default)

-Q display nothing, execute commands silently

-s Script-friendly mode. In this mode, show will not output titles for the items
shown. Also, module names will be printed instead of ID codes in pin, param, and
funct listings. Threads are printed on a single line, with the thread period, FP
usage and name first, followed by all of the functions in the thread, in execution
order. Signals are printed on a single line, with the type, value, and signal name
first, followed by a list of pins connected to the signal, showing both the
direction and the pin name.

-R Release the HAL mutex. This is useful for recovering when a HAL component has
crashed while holding the HAL mutex.

-v display results of each command

-V display lots of debugging junk

-h [<command>]
display a help screen and exit, displays extended help on command if specified

COMMANDS

Commands tell halcmd what to do. Normally halcmd reads a single command from the command
line and executes it. If the '-f' option is used to read commands from a file, halcmd
reads each line of the file as a new command. Anything following '#' on a line is a
comment.

loadrt modname
(load realtime module) Loads a realtime HAL module called modname. halcmd looks
for the module in a directory specified at compile time.

In systems with kernel-based realtime support (e.g. RTAI), halcmd calls the
linuxcnc_module_helper to load realtime modules. linuxcnc_module_helper is a
setuid program and is compiled with a whitelist of modules it is allowed to load.
This is currently just a list of LinuxCNC-related modules. The
linuxcnc_module_helper execs insmod, so return codes and error messages are those
from insmod. Administrators who wish to restrict which users can load these
LinuxCNC-related kernel modules can do this by setting the permissions and group on
linuxcnc_module_helper appropriately.

In systems with userspace-based realtime support (e.g. Preempt-RT) and in systems
without realtime support halcmd calls the rtapi_app which creates the realtime
environment (simulated realtime, on systems with no userspace realtime support) if
it did not yet exist, and then loads the requested component with a call to
dlopen(3).

unloadrt modname
(unload realtime module) Unloads a realtime HAL module called modname. If modname
is "all", it will unload all currently loaded realtime HAL modules. unloadrt also
works by execing linuxcnc_module_helper or rtapi_app, just like loadrt.

loadusr [flags] unix-command
(load Userspace component) Executes the given unix-command, usually to load a non-
realtime component. [flags] may be one or more of:

• -W to wait for the component to become ready. The component is assumed to have
the same name as the first argument of the command.

• -Wn name to wait for the component, which will have the given name.

• -w to wait for the program to exit

• -i to ignore the program return value (with -w)

waitusr name
(wait for Userspace component) Waits for non-realtime component name to disconnect
from HAL (usually on exit). The component must already be loaded. Useful near the
end of a HAL file to wait until the user closes some user interface component
before cleaning up and exiting.

unloadusr compname
(unload Userspace component) Unloads a non-realtime component called compname. If
compname is "all", it will unload all non-realtime components. unloadusr works by
sending SIGTERM to all non-realtime components.

unload compname
Unloads a non-realtime component or realtime module. If compname is "all", it will
unload all non-realtime components and realtime modules.

newsig signame type
(OBSOLETE - use net instead) (new signal) Creates a new HAL signal called signame
that may later be used to connect two or more HAL component pins. type is the data
type of the new signal, and must be one of "bit", "s32", "u32", or "float". Fails
if a signal of the same name already exists.

delsig signame
(delete signal) Deletes HAL signal signame. Any pins currently linked to the
signal will be unlinked. Fails if signame does not exist.

sets signame value
(set signal) Sets the value of signal signame to value. Fails if signame does not
exist, if it already has a writer, or if value is not a legal value. Legal values
depend on the signals's type.

stype name
(signal type) Gets the type of signal name. Fails if name does not exist as a
signal.

gets signame
(get signal) Gets the value of signal signame. Fails if signame does not exist.

linkps pinname [arrow] signame
(OBSOLETE - use net instead) (link pin to signal) Establishes a link between a HAL
component pin pinname and a HAL signal signame. Any previous link to pinname will
be broken. arrow can be "=>", "<=", "<=>", or omitted. halcmd ignores arrows, but
they can be useful in command files to document the direction of data flow. Arrows
should not be used on the command line since the shell might try to interpret them.
Fails if either pinname or signame does not exist, or if they are not the same type
type.

linksp signame [arrow] pinname
(OBSOLETE - use net instead) (link signal to pin) Works like linkps but reverses
the order of the arguments. halcmd treats both link commands exactly the same.
Use whichever you prefer.

linkpp pinname1 [arrow] pinname2
(OBSOLETE - use net instead) (link pin to pin) Shortcut for linkps that creates the
signal (named like the first pin), then links them both to that signal. halcmd
treats this just as if it were:
halcmd newsig pinname1
halcmd linksp pinname1 pinname1
halcmd linksp pinname1 pinname2

net signame pinname ...
Create signname to match the type of pinname if it does not yet exist. Then, link
signame to each pinname in turn. Arrows may be used as in linkps. When linking a
pin to a signal for the first time, the signal value will inherit the pin's default
value.

unlinkp pinname
(unlink pin) Breaks any previous link to pinname. Fails if pinname does not
exist. An unlinked pin will retain the last value of the signal it was linked to.

setp name value
(set parameter or pin) Sets the value of parameter or pin name to value. Fails if
name does not exist as a pin or parameter, if it is a parameter that is not
writable, if it is a pin that is an output, if it is a pin that is already attached
to a signal, or if value is not a legal value. Legal values depend on the type of
the pin or parameter. If a pin and a parameter both exist with the given name, the
parameter is acted on.

paramname = value

pinname = value
Identical to setp. This alternate form of the command may be more convenient and
readable when used in a file.

ptype name
(parameter or pin type) Gets the type of parameter or pin name. Fails if name
does not exist as a pin or parameter. If a pin and a parameter both exist with the
given name, the parameter is acted on.

getp name
(get parameter or pin) Gets the value of parameter or pin name. Fails if name
does not exist as a pin or parameter. If a pin and a parameter both exist with the
given name, the parameter is acted on.

addf functname threadname
(add function) Adds function functname to realtime thread threadname. functname
will run after any functions that were previously added to the thread. Fails if
either functname or threadname does not exist, or if they are incompatible.

delf functname threadname
(delete function) Removes function functname from realtime thread threadname.
Fails if either functname or threadname does not exist, or if functname is not
currently part of threadname.

start Starts execution of realtime threads. Each thread periodically calls all of the
functions that were added to it with the addf command, in the order in which they
were added.

stop Stops execution of realtime threads. The threads will no longer call their
functions.

show [item]
Prints HAL items to stdout in human readable format. item can be one of "comp"
(components), "pin", "sig" (signals), "param" (parameters), "funct" (functions),
"thread", or "alias". The type "all" can be used to show matching items of all the
preceding types. If item is omitted, show will print everything.

save [item]
Prints HAL items to stdout in the form of HAL commands. These commands can be
redirected to a file and later executed using halcmd -f to restore the saved
configuration. item can be one of the following:

"comp" generates a loadrt command for realtime component.

"alias" generates an alias command for each pin or parameter alias pairing

"sig" (or "signal") generates a newsig command for each signal, and "sigu"
generates a newsig command for each unlinked signal (for use with netl and netla).

"link" and "linka" both generate linkps commands for each link. (linka includes
arrows, while link does not.)

"net" and "neta" both generate one newsig command for each signal, followed by
linksp commands for each pin linked to that signal. (neta includes arrows.)

"netl" generates one net command for each linked signal, and "netla" (or "netal")
generates a similar command using arrows.

"param" (or "parameter) "generates one setp command for each parameter.

"thread" generates one addf command for each function in each realtime thread.

"unconnectedinpins" generates a setp command for each unconnected HAL input pin.

If item is allu), save does the equivalent of comp, alias, sigu, netla, param,
thread, and unconnectedinpins.

If item is omitted (or all), save does the equivalent of comp, alias, sigu, netla,
param, and thread.

source filename.hal
Execute the commands from filename.hal.

alias type name alias
Assigns "alias" as a second name for the pin or parameter "name". For most
operations, an alias provides a second name that can be used to refer to a pin or
parameter, both the original name and the alias will work.
"type" must be pin or param.
"name" must be an existing name or alias of the specified type. Note that the
"show" command will only show the aliased name, but the original name is still
valid to use in HAL. The original names can still be seen with "show all" or "show
alias" Existing nets will be preserved when a pin name is aliased.

unalias type alias
Removes any alias from the pin or parameter alias.
"type" must be pin or param
"alias" must be an existing name or alias of the specified type.

list type [pattern]
Prints the names of HAL items of the specified type.
'type' is 'comp', 'pin', 'sig', 'param', 'funct', or
'thread'. If 'pattern' is specified it prints only
those names that match the pattern, which may be a
'shell glob'.
For 'sig', 'pin' and 'param', the first pattern may be
-tdatatype where datatype is the data type (e.g., 'float')
in this case, the listed pins, signals, or parameters
are restricted to the given data type
Names are printed on a single line, space separated.

print [message]
Prints the filename, linenumber and an optional message.
wrap the message in quotes if it has spaces.

lock [all|tune|none]
Locks HAL to some degree.
none - no locking done.
tune - some tuning is possible (setp & such).
all - HAL completely locked.

unlock [all|tune]
Unlocks HAL to some degree.
tune - some tuning is possible (setp & such).
all - HAL completely unlocked.

status [type]
Prints status info about HAL.
'type' is 'lock', 'mem', or 'all'.
If 'type' is omitted, it assumes 'all'.

debug [level]
Sets the rtapi messaging level (see man3 rtapi_set_msg_level).

help [command]
Give help information for command.
If 'command' is omitted, list command and brief description.

SUBSTITUTION

       After  a command is read but before it is executed, several types of variable substitution
       take place.

   Environment Variables
       Environment variables have the following formats:

              $ENVVAR followed by end-of-line or whitespace

              $(ENVVAR)

   INI file variables
       INI file variables are available only when an INI file was specified with  the  halcmd  -i
       flag.  They have the following formats:

              [SECTION]VAR followed by end-of-line or whitespace

              [SECTION](VAR)

LINE CONTINUATION

       The backslash character (\) may be used to indicate the line is extended to the next line.
       The backslash character must be the last character before the newline.

BUGS

       None known at this time.

AUTHOR

       Original version by John Kasunich, as part of the LinuxCNC project.   Now  includes  major
       contributions by several members of the project.

REPORTING BUGS

       Report bugs to the LinuxCNC bug tracker ⟨http://sf.net/p/emc/bugs/⟩.

COPYRIGHT

       Copyright © 2003 John Kasunich.
       This  is  free software; see the source for copying conditions.  There is NO warranty; not
       even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.