Conky (http://conky.rty.ca)

  WHAT IS CONKY?

   Conky is a system monitor for Linux that sits in the corner of your
   desktop. Conky renders itself on the root window (on the desktop) or to
   its own transparent window any special eyecandy.
   Conky can show lots of info about your system, including:

     * kernel version
     * uptime
     * network interface information
     * memory and swap usage
     * hostname
     * machine, i686 for example
     * system name, Linux for example
     * temperatures from i2c-sensors

  THINGS YOU SHOULD KNOW

   Conky is generally very good on resources.  However, certain objects in
   Conky are harder on resources then others.  In particular, the $tail and
   $top objects are quite costly in comparison to the rest of Conky.
   If you do use them, please do not complain about memory or CPU usage,
   because you will simply be ignored.
   
   With that out of the way, if you have a better way of doing something,
   please submit a patch for Conky.  I know I am certainly not the world's
   best programmer, and I still have a lot to learn.

  COMPILING

   To compile and run Conky with all optional components (If you run Gentoo, see the "Ebuild" Section below):

         ./configure --prefix=/usr --enable-xft --enable-mpd --enable-seti --enable-double-buffer --enable-own-window --enable-proc-uptime 
         make
         ./conky

   Conky doesn't probably compile with other compilers than gcc and icc. It
   doesn't compile with C89 compiler and not even with pure C99. It uses few
   things that might not exist: strdup(), strcasecmp(), strncasecmp(), optarg
   variable with getopt() and long long (not in C89). Crashes in file system
   statistics stuff when compiled with icc, I don't know exactly why.

   You can disable 'drawing to own window' feature in case you don't need it
   by passing --disable-own-window to configure -script.

  EBUILD

   Conky is in Gentoo's Portage.  Simply use "emerge conky" to install conky.

  CONFIGURING

   Default configuration file is $HOME/.conkyrc (can be changed from
   conky.c among other things). See conkyrc.sample. You might want to copy
   it to $HOME/.conkyrc and then start modifying it.

    Configuration file confs

           Conf                                Meaning                        
   alignment             Aligned position on screen, may be top_left,         
                         top_right, bottom_left, bottom_right                 
   background            Boolean value, if true, Conky will be forked to     
                         background when started                              
   border_margin         Border margin in pixels                              
   border_width          Border width in pixels                               
   cpu_avg_samples       The number of samples to average for CPU monitoring
   default_color         Default color and border color                       
   default_shade_color   Default shading color and border's shading color     
   default_outline_color Default outline color                                
                         Use the Xdbe extension? (eliminates flicker) It is   
   double_buffer         highly recommended to use own window with this one   
                         so double buffer won't be so big.                    
   draw_borders          Draw borders around text?                            
   draw_shades           Draw shades?                                         
   draw_outline          Draw outlines?                                       
   font                  Font name in X, xfontsel can be used to get a nice   
                         font                                                 
   gap_x                 Gap between right or left border of screen, same as
                         passing -x at command line
   gap_y                 Gap between top or bottom border of screen, same as
                         passing -y at command line
   no_buffers            Substract (file system) buffers from used memory?    
   mail_spool            Mail spool for mail checking                         
   metar_station         METAR station code for weather, see
                         http://www.wrh.noaa.gov/ if you need to find
			 your code.
   metar_server          Define a custom METAR ftp server
   metar_path            Path on server to use
   minimum_size          Minimum size of window                               
   mldonkey_hostname     Hostname for mldonkey stuff, defaults to localhost
   mldonkey_port         Mldonkey port, 4001 default
   mldonkey_login        Mldonkey login, default none
   mldonkey_password     Mldonkey password, default none
   net_avg_samples       The number of samples to average for net data
   override_utf8_locale  Force UTF8? requires XFT
   own_window            Boolean, create own window to draw?                  
   pad_percents          Pad percentages to this many decimals (0 = no        
                         padding)                                             
   stippled_borders      Border stippling (dashing) in pixels                 
   total_run_times       Total number of times for Conky to update before
                         quitting.  Zero makes Conky run forever
   update_interval       Update interval in seconds                           
   uppercase             Boolean value, if true, text is rendered in upper    
                         case                                                 
   use_spacer            Adds spaces after certain objects to stop them
                         from moving other things around.  Note that
			 this only helps if you are using a mono font,
			 such as Bitstream Vera Sans Mono.
   use_xft               Use Xft (anti-aliased font and stuff)                
   text                  After this begins text to be formatted on screen     

   Boolean variable without value in text means yes. Value may be also yes,
   true or any negative or positive integer meaning yes. No, false or zero
   meaning no.
   There may be some variables in text. Variable is given either in format
   $variable or in ${variable}. Latter allows characters right after the
   variable and must be used in some stuff because of arguments.

    Command line options

     Argument                          Description                        
   -V           Prints version and exits                                  
   -a ALIGNMENT Text alignment on screen, {top,bottom}_{left,right}       
   -b           Use double buffering (eliminates flicker)                 
   -c FILE      Config file to load instead of $HOME/.conkyrc            
   -d           Daemonize, fork to background                             
   -f FONT      Font to use                                               
   -h           Prints command line help and exits                        
   -o           Create own window to draw                                 
   -t TEXT      Text to render, remember single quotes, like -t '$uptime' 
   -u SECS      Update interval                                           
   -w WIN_ID    Window id to draw                                         
   -x X         X position                                                
   -y Y         Y position                                                

   Command line options override configurations defined in configuration
   file.

    Variables in text

       Variable          Arguments                   Description              

  addr              (interface)     IP address for an interface
  acpiacadapter                     ACPI ac adapter state.                   
  acpifan                           ACPI fan state                           
  acpitemp                          ACPI temperature.                        
  adt746xcpu                        CPU temperature from therm_adt746x       
  adt746xfan                        Fan speed from therm_adt746x             
  alignr            (num)           Right-justify text, with space of N
  alignc                            Align text to centre
  battery           (num)           Remaining capasity in ACPI or APM        
                                    battery. ACPI battery number can be      
                                    given as argument (default is BAT0).     
  buffers                           Amount of memory buffered                
  cached                            Amount of memory cached                  
  color             (color)         Change drawing color to color            
  cpu                               CPU usage in percents                    
  cpubar            (height)        Bar that shows CPU usage, height is      
                                    bar's height in pixels                 
  cpugraph          (height),(width)CPU usage graph
  downspeed         net             Download speed in kilobytes              
  downspeedf        net             Download speed in kilobytes with one     
                                    decimal                                  
  downspeedgraph    net (height),(width) Download speed graph
  exec              shell command   Executes a shell command and displays    
                                    the output in conky. warning: this      
                                    takes a lot more resources than other    
                                    variables. I'd recommend coding wanted   
                                    behaviour in C and posting a patch :-).  
  execbar           shell command   Same as exec, except if the first value
                                    return is a value between 0-100, it
                                    will use that number for a bar.
                                    The size for the bar is currently fixed,
                                    but that may change in the future.
  execgraph         shell command   Same as execbar, but graphs values
  execi             interval, shell Same as exec but with specific interval. 
                    command         Interval can't be less than              
                                    update_interval in configuration.        
  fs_bar            (height), (fs)  Bar that shows how much space is used on 
                                    a file system. height is the height in   
                                    pixels. fs is any file on that file      
                                    system.                                  
  fs_free           (fs)            Free space on a file system available    
                                    for users.                               
  fs_free_perc      (fs)            Free percentage of space on a file       
                                    system available for users.              
  fs_size           (fs)            File system size                         
  fs_used           (fs)            File system used space                   
  hr                (height)        Horizontal line, height is the height in 
                                    pixels                                   
  i2c               (dev), type, n  I2C sensor from sysfs (Linux 2.6). dev   
                                    may be omitted if you have only one I2C  
                                    device. type is either in (or vol)       
                                    meaning voltage, fan meaning fan or
				    temp/tempf (first in C, second in F)
                                    meaning temperature. n is number of the  
                                    sensor. See /sys/bus/i2c/devices/ on     
                                    your local computer.                     
  if_running        (process)       if PROCESS is running, display
                                    everything if_running and the matching $endif
  if_existing       (file)          if FILE exists, display everything between
                                    if_existing and the matching $endif
  if_mounted        (mountpoint)    if MOUNTPOINT is mounted, display everything between
                                    if_mounted and the matching $endif
  else                              Text to show if any of the above are not true
  kernel                            Kernel version                          
  linkstatus        (interface)     Get the link status for wireless connections
  loadavg           (1), (2), (3)   System load average, 1 is for past 1     
                                    minute, 2 for past 5 minutes and 3 for   
                                    past 15 minutes.                         
  machine                           Machine, i686 for example                
  mails                             Mail count in mail spool. You can use    
                                    program like fetchmail to get mails from 
                                    some server using your favourite         
                                    protocol. See also new_mails.            
  mem                               Amount of memory in use                  
  membar            (height)        Bar that shows amount of memory in use   
  memmax                            Total amount of memory                   
  memperc                           Percentage of memory in use
  
  metar_ob_time
  metar_temp
  metar_tempf                      Temp in F
  metar_windchill
  metar_dew_point                   There are a bunch of these
  metar_rh                          and they are self-explanatory
  metar_windspeed
  metar_winddir
  metar_swinddir
  metar_cloud
  metar_u2d_time

  ml_upload_counter                 total session upload in mb
  ml_download_counter               total session download in mb
  ml_nshared_files                  number of shared files
  ml_shared_counter                 total session shared in mb, buggy
                                    in some mldonkey versions
  ml_tcp_upload_rate                tcp upload rate in kb/s
  ml_tcp_download_rate              tcp download rate in kb/s
  ml_udp_upload_rate                udp upload rate in kb/s
  ml_udp_download_rate              udp download rate in kb/s
  ml_ndownloaded_files              number of completed files
  ml_ndownloading_files             number of downloading files
  
  mpd_artist			    Artist in current MPD song
                                    (must be enabled at compile)
  mpd_album			    Album in current MPD song
  mpd_bar           (height)        Bar of mpd's progress
  mpd_bitrate                       Bitrate of current song
  mpd_status                        Playing, stopped, et cetera.
  mpd_title			    Title of current MPD song
  mpd_vol			    MPD's volume
  mpd_elapsed                       Song's elapsed time
  mpd_length                        Song's length
  mpd_percent                       Percent of song's progress
  new_mails                         Unread mail count in mail spool.         
  nodename                          Hostname                                 
  outlinecolor      (color)         Change outline color                     
  pre_exec          shell command   Executes a shell command one time before 
                                    conky displays anything and puts output 
                                    as text.                                 
  processes                         Total processes (sleeping and running)   
  running_processes                 Running processes (not sleeping),        
                                    requires Linux 2.6                       
  shadecolor        (color)         Change shading color                     
  stippled_hr       (space),        Stippled (dashed) horizontal line        
                    (height)        
  swapbar           (height)        Bar that shows amount of swap in use     
  swap                              Amount of swap in use                    
  swapmax                           Total amount of swap                     
  swapperc                          Percentage of swap in use                
  sysname                           System name, Linux for example           
  offset            pixels          Move text over by N pixels
  tail              logfile, lines (interval)
                                    Displays last N lines of supplied text
                                    text file.  If interval is not supplied,
                                    Conky assumes 2x Conky's interval.
                                    Max of 30 lines.
                                    Max of 30 lines can be displayed.
  time              (format)        Local time, see man strftime to get more 
                                    information about format                 
  totaldown         net             Total download, overflows at 4 GB on     
                                    Linux with 32-bit arch and there doesn't 
                                    seem to be a way to know how many times  
                                    it has already done that before conky   
                                    has started.                            
  top               type, num      This takes arguments in the form:
                                    top <name> <number>
                                    Basically, processes are ranked from 
                                    highest to lowest in terms of cpu
                                    usage, which is what <num> represents.
                                    The types are: "name", "pid", "cpu", and
                                    "mem".
                                    There can be a max of 10 processes listed.
  top_mem           type, num       Same as top, except sorted by mem usage
                                    instead of cpu
  totalup           net             Total upload, this one too, may overflow 
  updates                           Number of updates (for debugging)        
  upspeed           net             Upload speed in kilobytes                
  upspeedf          net             Upload speed in kilobytes with one       
                                    decimal                                  
  upspeedgraph      net (height),(width) Upload speed graph
  uptime                            Uptime                                   
  uptime_short                      Uptime in a shorter format               

  seti_prog                         Seti@home current progress
  seti_progbar      (height)        Seti@home current progress bar
  seti_credit                       Seti@hoome total user credit


   colors are parsed using XParsecolor(), there might be a list of them:
   /usr/X11R6/lib/X11/rgb.txt. color can be also in #rrggbb format (hex).

   Note that when displaying bytes, power is 1024 and not 1000 so 1M really
   means 1024*1024 bytes and not 1000*1000.

  KNOWN PROBLEMS

   Drawing to root or some other desktop window directly doesn't work with
   all window managers. Especially doesn't work well with Gnome and it has
   been reported that it doesn't work with KDE either. Nautilus can be
   disabled from drawing to desktop with program gconf-editor. Uncheck
   show_desktop in /apps/nautilus/preferences/. There is -w switch in Conky
   to set some specific window id. You might find xwininfo -tree useful to
   find the window to draw to. You can also use -o argument which makes
   Conky to create its own window.