Need help with a script to remind at intervals.

[krugan]

Hi,

I am trying to write a shell script that will remind me to leave 10, 5, 2 ,1 minute before the time given to leave and remind every minute after until I log out. I know I can do this with the sleep command but, how can I do it without tying up my terminal in between messages?

 

[marsd]

Here's a simple alarm program in tcl.
Using Tclx you can call the main portion with fork(),
to get the script into the bg..
if {[set myid [fork]] == 0} {
#main code
} else {
exit
}
or, just call the script with the ampersand appended in
bash and some compliant shells.
ex: tclsh myscript.tcl "15:30:00"&

Here is the code. I'm not going to explain a lot of it.
If you understand, great, if not, well, you can experiment.

#!/usr/bin/tclsh
#globals and procedures##
#time specific variables

set tm [lindex $argv 0]

array set alarms {
ten "600000"
five "300000"
two "120000"
one "60000"
interval "3000"
}

#stateful variables array
array set flag {
10 0
5  0
2 0
1 0
}

#recursive controller,better with more controlled
#and flexible tests than the switch.
proc WakeUp {} {
global flag alarms activetime tm
    switch -exact -- $activetime      [expr [clock seconds] - $alarms(ten) / 1000] {
              set flag(10) 1
              return 0

     } [expr [clock seconds] - $alarms(five) / 1000]  {
             set flag(five) 1
             return 0

     } [expr [clock seconds] - $alarms(two) / 1000]  {
             set flag(two) 1
             return 0
    
    } [expr [clock seconds] - $alarms(ten) / 1000]  {
            set flag(one) 1
            return 0
    }
#final check
       if {[clock seconds] >= $activetime} {
          set flag(one) 1
          return 0
       }

#recall/reset if nothing else
set activetime [clock scan "today"  -base [clock scan $tm]]
after $alarms(interval) {WakeUp}
}
 
#trace handler for time-state.
proc alarmHandler {var val op} {
global flag alarms
     if {[string compare $val "ten"] == 0} {
         send_warning $val
         after $alarms(five) {uplevel #0 "set flag(ten) 0"}
         return $val
     } elseif {[string compare $val "five"] == 0} {
         send_warning $val
         after $alarms(two) {uplevel #0 "set flag(five) 0"}
         return $val       
     } elseif {[string compare $val "two"] == 0} {
         send_warning $val
         after $alarms(one) {uplevel #0 "set flag(two) 0"}
         return $val       
     } elseif {[string compare $val "one"] == 0} {
         send_warning $val
         after $alarms(one) {uplevel #0 "set flag(one) 0"}
         return $val       
     } 
return 0
}

#uses the op of who and a static declaration to
#warn the user. tcl is not big on ascii art.
#you could check out tk for a popup. it would
#be trivial to code.
proc send_warning {v} {
global user flag
set out [exec who]

        for {set x 0} {$x <= [llength $out]} {incr x 5} {
            if {[string compare $user [lindex $out $x]] == 0} {
               puts &quot;\n\n*******************USER:$user*******************************************&quot;
               puts &quot;Please logout $user, you are in alarm cycle at $v minute intervals&quot;
               puts &quot;*******************WARNING:$v minutes till next check*******************\r\n&quot;
            }
        }
  #kludge for trace termination
  #sometimes traces seem to die with older
  #pre 8.4 tcl..
  if {![llength [trace info variable flag]]} {
     puts &quot;NO trace detected :: reinit called..&quot;
     uplevel #0 {trace add variable flag write {alarmHandler}}
     return 1
  }
return 0
}





#idiot check and main()
#give the time you are excused 
#in this form->say 5:30pm? = &quot;17:30:00&quot;
     if {![string length [lindex $argv 0]]} {
        error &quot;You must give me a base time in hour:minute:second format!!&quot;
     }
        #the user who calls the script is the 
        #user searched for in send_warning
        set user $env(USER)
        #every day the given time needs to be changed
        #do this in WakeUp
        set activetime [clock scan &quot;today&quot;  -base [clock scan $tm]]
        #our event code below
        trace add variable flag write {alarmHandler}
        WakeUp
        vwait forever

Good Luck