Tuesday, April 10, 2007

getting a list of all users currently connected to Smallworld

I learned a new aspect of Windows command-line scripting the other day that I thought might be worth sharing here.

The requirement was to get a list of all users connected to a particular swmfs server and notify them that the server was about to go down.

I discovered that the FOR command is just what the doctor ordered for this task. The basic form is as follows...

FOR /F "skip=5 delims=@" %%i IN ('swmfs_list -full \\%COMPUTERNAME%\sw400\product\data message.ds') DO net send %%i Smallworld server going down in 2 minutes.


Where...

  • FOR /F ... IN ...
    • Command key words that tell the system that you want to iteratively process the results of some file or command
  • ('swmfs_list -full \\%COMPUTERNAME%\sw400\product\data message.ds')
    • the command that will have each line processed individually for some information. This particular command provides a list of all the user@computername that are connected to message.ds in the specified folder on %COMPUTERNAME%
  • %%i
    • the internal variable representing each line of the file/command
  • "skip=5 delims=@"
    • instructions to the command to skip the first 5 lines of swmfs_list and then also split the processed lines by the @ character.
  • DO
    • a command key word that indicates that what follows next is the command to be processed on each line of iterator
  • net send %%i Smallworld server going down in 2 minutes.
    • the NET SEND command is used to send the message "Smallworld server going down in 2 minutes" to the user specified in variable %%i. Remember that the variable %%i represents the first element of each line after it has been split by the @ character.
I hope you find this useful.

3 comments:

linuxdave said...

Nice script, Alfred. Should come in handy! Thanks!

Anonymous said...

Nice.. script is there a Magik equavalent method to get connected users and add them to a rope??

Alfred Sawatzky said...

_block
# returns all the users currently connected to
# c:\smallworld41\product\data\message.ds
#
# modify as required

_local str << system.input_from_command({"swmfs_list","-full","c:\smallworld41\product\data","message.ds"})

_local a_line
_local users << equality_set.new()

_loop
_if (a_line << str.get_line()) _is _unset
_then
_leave
_endif

# we are only interested in the lines that have @ in them
# because those are the ones that indicate user information.
_if a_line.index_of(%@) _isnt _unset
_then
# if we are on a user line, then take the string up to the
# first space_char as the user ID.
users.add(a_line.split_by(space_char).first)
_endif
_endloop

# show results
print(users)

_endblock
$