reading text

set script "$portpath $verboselevel selfupdate > [file join $::env(TMPDIR) portauthority.txt] 2>&1 &"

    set scripterr {   
	AppleScript execute "

do shell script \"$script\"  with administrator privileges

"
    }
    
    if {[catch $scripterr errmsg]} {endProgress; tk_messageBox -icon warning -parent . -message "Error" -detail "The following output was returned: $errmsg"; return}

   # set fd [open "|tail -f  [file join $::env(TMPDIR) portauthority.txt]" r]
    set fd [open [file join $::env(TMPDIR) portauthority.txt] r]
    puts "reading file"
    
    fconfigure $fd -blocking 0 -buffering none
    fileevent $fd readable [list logging_command $fd]
    vwait done
    set status "Done"

#process to log items in text display
proc logging_command {fd} {
    
    global log
    global done 
    global pipe

    set pipe $fd

    #using catch for the case that the file somehow is already closed
    if {[catch {set isclosed [eof $fd]}] || $isclosed} {
	catch {close $fd}
	set done 1
	return
    }

    #using catch for the case that the file somehow is already closed
    #if the pipe is closed, gets will produce an error!!!
    if {[catch {set data [read $fd]}]} {
	catch {close $fd}
	set done 1
	return
    }

    urltext::inserttext $data\n
    
}