What day is today?
========================

I recently discovered that a unix tool that I use on a daily basis is
practically unknown to most of the people I have asked about it. This
tool is cal(1):

  $ cal
      September 2020     
   Su Mo Tu We Th Fr Sa  
          1  2  3  4  5  
    6  7  8  9 10 11 12  
   13 14 15 16 17 18 19  
   20 21 22 23 24 25 26  
   27 28 29 30           
   
Yes, if run without any argument, cal(1) just prints the calendar of the
current month. But it can also print the calendar of any months in any
year:

  $ cal 9 1972
      September 1972     
   Su Mo Tu We Th Fr Sa  
                   1  2  
    3  4  5  6  7  8  9  
   10 11 12 13 14 15 16  
   17 18 19 20 21 22 23  
   24 25 26 27 28 29 30  

or the whole calendar of a year, if you see what I mean (i.e., if you
read the manpage). I think it is nowadays mainly forgotten because very
few people nowadays use a computer from the command line only (yes,
having a shiny calendar app is unfortunately the norm for many a "unix
enthusiast"). 

Just avoid to get confused with calendar(1), which will probably print
nothing at all in your system :P

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cal(1)   	appeared in UNIXv5 (1974)
calendar(1)	appeared in UNIXv7 (1979)

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