Colorear logs

En la página de Christian Schneider, (programador alemán  Linux, Perl, Html, Css y PHP - guru , originario de la preciosa ciudad de Regensburg http://www.strcat.de/ ), encontré un script para colorear la salida por terminal, de los logs, mensajes del kernel (dmesg), etc de manera que resulte más facil su lectura.

Es un script en Perl de nombre colorlog.pl Utilizando un editor de texto lo guardamos en, por ejemplo, /usr/bin con permisos de ejecución.

#!/usr/bin/perl
 
$black    = "\033[30m";
$red      = "\033[31m";
$green    = "\033[32m";
$yellow   = "\033[33m";
$blue     = "\033[34m";
$magenta  = "\033[35m";
$purple   = "\033[35m";
$cyan     = "\033[36m";
$white    = "\033[37m";
$darkgray = "\033[30m";
@word_good=("starting\n", "Freeing", "Detected", "starting.", "accepted.\n", "authenticated.\n", "Ready", "active", "reloading", "saved;", "restarting", "ONLINE\n");
@word_warn=("dangling", "closed.\n", "Assuming", "root", "root\n", "exiting\n", "missing", "Ignored", "adminalert:", "deleting", "OFFLINE\n");
@word_bad=("bad");
@word_note=("LOGIN", "DHCP_OFFER", "optimized", "reset:", "unloaded", "disconnected", "connect", "Successful", "registered\n");
@line_good=("up", "DHCP_ACK", "Cleaned", "Initializing", "Starting", "success", "successfully", "alive", "found", "ONLINE\n");
@line_warn=("warning:", "WARNING:", "invalid", "obsolete", "bad", "Password", "detected", "timeout", "timeout:", "attackalert:", "wrong", "Lame", "FAILED", "failing", "unknown", "obsolete", "stopped.\n", "terminating.", "disabled\n", "disabled", "Lost");
@line_bad=("DENY", "lost", "shutting", "dead", "DHCP_NAK", "failure;", "Unable", "inactive", "terminating", "refused", "rejected", "down", "OFFLINE\n", "error\n", "ERROR\n", "ERROR:", "error", "ERROR", "error:", "failed:");
@daemons=("named");
$col_good = $green;
$col_warn = $yellow;
$col_bad = $red;
$col_note = $purple;
$col_norm =  "\033[00m";
$col_background = "\033[07m";
$col_brighten =  "\033[01m";
$col_underline =  "\033[04m";
$col_blink =   "\033[05m";
$col_default = "$col_norm$white";
print "$col_norm$cyan";
$datespace=0;
mainloop: while (<>)
{
 $thisline = $_;
 $timestamp = substr($_,0,15);
 s/................//;
 @rec = split (/ /, $_);
 $output="$col_brighten$cyan$timestamp"; 
 $output.=" $col_brighten$blue$rec[0]"; 
 if ($rec[1] eq "last")
 {
  $output.="$col_norm$green last message repeated ";
  $output.="$col_brighten$rec[4]$col_norm$green times\n";
  print "$output$col_default";
  next mainloop;
 }
 if ($rec[1] =~ /\[(\d+)\]\:/)
 {
  my($pid) = $1;
  $rec[1]=~s/\[$1\]\:// ;
  $output .= "$col_norm$green $rec[1]" .
             "$col_brighten$green\[";
  $output .= "$col_brighten$white$pid" .
             "$col_brighten$green\]: ";
 }
 else {
  $output .= "$col_norm$green $rec[1] ";
 }
 $restcolor="$col_norm$cyan";
 $restoftheline="";
 for ($therest=(2); $therest<=$#rec; $therest++)
 { $highlight=0;
  for ($i=0; $i<=$#word_good; $i++)
  { if ($word_good[$i] eq $rec[$therest])
   { $restoftheline.="$col_brighten$col_good"; $highlight=1; }
  }
  for ($i=0; $i<=$#word_warn; $i++)
  { if ($word_warn[$i] eq $rec[$therest])
   { $restoftheline.="$col_brighten$col_warn"; $highlight=1; } 
  }
  for ($i=0; $i<=$#word_bad; $i++)
  { if ($word_bad[$i] eq $rec[$therest])
   { $restoftheline.="$col_brighten$col_bad"; $highlight=1; } 
  }
  for ($i=0; $i<=$#word_note; $i++) 
  { if ($word_note[$i] eq $rec[$therest])
   { $restoftheline.="$col_brighten$col_note"; $highlight=1; } 
  }
  for ($i=0; $i<=$#line_good; $i++)
  { if ($line_good[$i] eq $rec[$therest])
   { $restcolor="$col_norm$col_good";
     $restoftheline.="$col_brighten$col_good"; $highlight=1; }
  }
  for ($i=0; $i<=$#line_warn; $i++)
  { if ($line_warn[$i] eq $rec[$therest])
   { $restcolor="$col_norm$col_warn";
     $restoftheline.="$col_brighten$col_warn"; $highlight=1; }
  }
  for ($i=0; $i<=$#line_bad; $i++)
  { if ($line_bad[$i] eq $rec[$therest])
   { $restcolor="$col_norm$col_bad";
     $restoftheline.="$col_brighten$col_bad"; $highlight=1; }
  }
  $restoftheline.="$rec[$therest] ";
  if ($highlight == 1)
  { $restoftheline.=$restcolor; }
 }
 $output.="$restcolor$restoftheline";
 print "$output$col_default\033[1G";
}
exit(0);

Ejemplos de utilización:

cat /var/log/dmesg | colorlog.pl | less

tail -n 20 /var/log/messages | colorlog.pl

tail -n 20 /var/log/dmesg | colorlog.pl

Linux es genial!.