'''flog ''' ''filename-prefix ''- Follow LOGs matching the prefix supplied, outputting updates to them as they arrive.
Like `tail -f` but switches to the newest file whose name starts with the prefix supplied.
I wrote this for when I need to watch the latest log in a series whose names contain a date/time-stamp or sequence number [CGM].

----

  #!/usr/bin/env tclsh
  
  if {$argc != 1 } {
      puts "Usage: $argv0 <filename-prefix>"
      puts "- Follow LOG files matching prefix, outputting contents of newest as updated"
      exit
  }
  
  proc newest prefix {
      set lt 0
      set lf {}
      foreach f [glob -nocomplain -types {f r} -- $prefix*] {
  
          if {[catch {file mtime $f} t]} continue
          if {$t > $lt} {
              set lt $t
              set lf $f
          }
      }
      return $lf
  }
  
  set prefix [lindex $argv 0]
  
  set nf [newest $prefix]
  while 1 {
  
      while {$nf eq {}} {
          after 1000
          set nf [newest $prefix]
      }
  
      set cf $nf
      puts stderr "Following: $cf"
      set if [open $cf]
  
      while {$nf eq $cf} {
          if {[file size $cf] < [tell $if]} break
          puts -nonewline [read $if]
          after 1000
          set nf [newest $prefix]
      }
      puts -nonewline [read $if]
      close $if
  }