exec command and set ballon for systray icon

systray.tk

#!/usr/bin/wish

array set fonts {
        main {-*-fixed-bold-r-*-*-13-*-*-*-*-*-iso10646-1}
}

# default command:
set command exec 
lappend command curl
lappend command -s
lappend command http://wttr.in/?0&q&T

# re-set command by cli arguments
if { $::argc > 0 } {
    set command exec
    foreach arg $::argv {
        lappend command $arg
    }
}
# interval between executions of command
set interval 300000

# icon in base64, taken from old mpd control script
set STOP { 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}

image create photo stop_img -data $STOP

package require tktray

# procedures taken from http://wiki.tcl.tk/16317 and sligthly modified
 proc setBalloonHelp {w msg args} {
     array set opt [concat {
         -tag ""
     } $args]
     if {$msg ne ""} then {
         set toolTipScript\
             [list showBalloonHelp %W [string map {% %%} $msg]]
         set enterScript [list after 300 $toolTipScript]
         set leaveScript [list after cancel $toolTipScript]
         append leaveScript \n [list after 200 [list destroy .balloonHelp]]
     } else {
         set enterScript {}
         set leaveScript {}
     }
     if {$opt(-tag) ne ""} then {
         switch -- [winfo class $w] {
             Text {
                 $w tag bind $opt(-tag) <Enter> $enterScript
                 $w tag bind $opt(-tag) <Leave> $leaveScript
             }
             Canvas {
                 $w bind $opt(-tag) <Enter> $enterScript
                 $w bind $opt(-tag) <Leave> $leaveScript
             }
             default {
                 bind $w <Enter> $enterScript
                 bind $w <Leave> $leaveScript
             }
         }
     } else {
         bind $w <Enter> $enterScript
         bind $w <Leave> $leaveScript
     }
 }

 proc showBalloonHelp {w msg} {
     global ::fonts
     set t .balloonHelp
     catch {destroy $t}
     toplevel $t -bg black
     wm overrideredirect $t yes
     if {$::tcl_platform(platform) == "macintosh"} {
         unsupported1 style $t floating sideTitlebar
     }
     pack [label $t.l -text $msg -justify left -bg yellow -font $fonts(main)]\
         -padx 1\
         -pady 1
     set width [expr {[winfo reqwidth $t.l] + 2}]
     set height [expr {[winfo reqheight $t.l] + 2}]
     set xMax [expr {[winfo screenwidth $w] - $width}]
     set yMax [expr {[winfo screenheight $w] - $height}]
     set x [winfo pointerx $w]
     set y [expr {[winfo pointery $w] + 20}]
     if {$x > $xMax} then {
         set x $xMax
     }
     if {$y > $yMax} then {
         set y $yMax
     }
     wm geometry $t +$x+$y
     set destroyScript [list destroy .balloonHelp]
     bind $t <Enter> [list after cancel $destroyScript]
     bind $t <Leave> $destroyScript
 }


proc update_balloon {} {
    global ::command
    global ::interval
    set result ""
    try {
        set result [eval $command]
    }
    setBalloonHelp .trayicon $result
    after $interval update_balloon
}

tktray::icon .trayicon -class TestTray -image stop_img
update_balloon

wm withdraw .