SLUG_Wiki: Network Status Using Cron

Hang on... working on it!!

Something for cron:

 #!/bin/sh
 if ping -c 1 -w 1 foo >/dev/null; then
    echo okay
 else
    echo shoot
 fi

And a standalone script I'm using on one box:

 #!/usr/local/bin/tclsh

 # network heartbeat monitor for my machines
 # with Orinoco PCMCIA wireless network cards
 # which unaccountably go kerflooey whenever
 # they are put into promiscuous mode ;^(

 set fid [ open /var/log/netbeat.log a+ 0644 ]
 puts $fid "[ clock format [ clock seconds ] ] desktop:80: netbeat pid: [ pid ]"
 close $fid

 while { 1 } {
    if { [ catch { 
       set sid [ socket -async desktop 80 ]
    } err ] } {
       set fid [ open /var/log/netbeat.log a+ 0644 ]
       puts $fid "[ clock format [ clock seconds ] ] desktop:80: $err"
       close $fid 
    }
    after 1000
    if { [ catch { fconfigure $sid -peername } ] } { 
       set fid [ open /var/log/netbeat.log a+ 0644 ]
       puts $fid "[ clock format [ clock seconds ] ] desktop:80: calling 'cardctl reset'"
       close $fid
       catch { exec cardctl reset }
       after 60000
    } else {
       close $sid
    }
    after 9000
 }

And a newer version of the same:

 #!/usr/local/bin/tclsh

 # network heartbeat monitor for my machines
 # with Orinoco PCMCIA wireless network cards
 # which unaccountably go kerflooey whenever
 # they are put into promiscuous mode ;^(

 # configuration options
 set ::host desktop # another host on the lan
 set ::port 80      # the port on the other host to 'ping'
 set ::logfile /var/log/netbeat.log
 set ::kills [ list netwatch mozilla ]

 # log pid at startup
 proc init { args } {
    log "netbeat pid: [ pid ]" 
 }

 proc sleep { seconds } {
    set seconds [ expr int($seconds) ]
    if { $seconds > 1000 } {
       set seconds [ expr { $seconds / 1000 } ]
    }
    after [ expr { $seconds * 1000 } ]
 }

 # generic logging function
 proc log { args } {
    set timestamp [ clock format [ clock seconds ] ]
    set fid [ open $::logfile a+ 0644 ]
    puts $fid "${timestamp}: ${::host}:${::port}: $args"
    close $fid
 }

 # this works for me!
 proc reset { args } {
      log "calling 'cardctl reset'"
      catch { exec cardctl reset }
      # avoid banging on hardware too often
      # if the reset fails.
      sleep 60
 }

 # kill things that might be problems
 proc kill { args } {
      foreach program $::kills {
         catch { exec pkill -9 $program }
      }
 }

 init

 while { 1 } {
    if { [ catch {
       set sid [ socket -async $::host $::port ]
       sleep 1
    } err ] } {
       log $err
    }
    # peerinfo will be unavailable if socket open failed
    if { [ catch { fconfigure $sid -peername } ] } { 
       kill
       reset
    } else {
       close $sid
    }
    sleep 19
 }