Cal command help.

[lerner]

Here is the problem:

This is what I get when I do the man cal command:

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-M      Weeks start on Monday.

This is what happens when I do that in the CLI:

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pi@PIFACE:~/Mine $ cal -M
Usage: cal [general options] [-hjy] [[month] year]
       cal [general options] [-hj] [-m month] [year]
       ncal [general options] [-bhJjpwySM] [-s country_code] [[month] year]
       ncal [general options] [-bhJeoSM] [year]
General options: [-NC31] [-A months] [-B months]
For debug the highlighting: [-H yyyy-mm-dd] [-d yyyy-mm]
pi@PIFACE:~/Mine $ 

So I am confused.
The command's MAN page shows that -M is allowed, to start weeks with Monday.
Yet, when I do the command, it rejects it.

Huh?

[rpdom]

That man page shows that the -M option works with the ncal command, not cal.

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pi@raspi8:~ $ cal -M
Usage: cal [general options] [-hjy] [[month] year]
       cal [general options] [-hj] [-m month] [year]
       ncal [general options] [-bhJjpwySM] [-s country_code] [[month] year]
       ncal [general options] [-bhJeoSM] [year]
General options: [-NC31] [-A months] [-B months]
For debug the highlighting: [-H yyyy-mm-dd] [-d yyyy-mm]
pi@raspi8:~ $ ncal -M
    September 2016    
Mo     5 12 19 26   
Tu     6 13 20 27   
We     7 14 21 28   
Th  1  8 15 22 29   
Fr  2  9 16 23 30   
Sa  3 10 17 24      
Su  4 11 18 25      
pi@raspi8:~ $ 

[lerner]

Well, the error message says that - which I admit I didn't understand. - but I entered:

MAN CAL (lower case) and got the result posted.

So to me, the MAN is mis-leading.


Now, ok, ncal -M works and gives me the week starting monday.
But that is vertical but cal gives you the month horizontal.

Is this the start of a confusing journey?

[Paeryn]

Well, the error message says that - which I admit I didn't understand. - but I entered:

MAN CAL (lower case) and got the result posted.

So to me, the MAN is mis-leading.

It isn't misleading, at the top of the man page it clearly lists which commands takes which arguments, -M is only listed for ncal.

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SYNOPSIS
     cal [-3hjy] [-A number] [-B number] [[month] year]
     cal [-3hj] [-A number] [-B number] -m month [year]
     ncal [-3bhjJpwySM] [-A number] [-B number] [-s country_code] [[month]
         year]
     ncal [-3bhJeoSM] [-A number] [-B number] [year]
     ncal [-CN] [-H yyyy-mm-dd] [-d yyyy-mm]

[lerner]

Yeah, ok, now after really looking I admit it also includes ncal.

But I seem to be put off that although it declares ncal as an alternative command, I asked for CAL.
Not NCAL.
So if I enter: MAN CAL, I am expecting the commands for CAL. If I wanted the commands for NCAL, I would have entered MAN NCAL.

But that's me.

Now I know, I shall try to be more diligent reading MAN pages in the future.

[jbudd]

ncal -b displays the days across the top,

On my Pi ncal starts the week with monday anyway but maybe that's part of the locale settings. Anyway ncal -Mb should work.

ps man pages are often impenetrable and confusing. Probably better for jogging the memory than learning from.

[lerner]

Thanks.

Seems I need ncal -bM

[Paeryn]

There are a lot of cases where man pages cover more than one thing, they will all be related however. This is helpful where they are variations of a similar thing.

In this case you have the original cal and the newcal, both programs do the same thing but in different ways. By having them in the same man page you immediately get to see both choices and you can decide which you need to use to get what you want without having to switch between 2 sets of man pages.

[W. H. Heydt]

ps man pages are often impenetrable and confusing. Probably better for jogging the memory than learning from.

That's probably because the man pages started life as the programmers reference manual. They're for looking things up more that learning from. *Most* manuals are like that.

If the man pages are to opaque to learn from, use your favorite search engine for instructional materials.

[dasmanul]

On a side note, cal and ncal are actually the same program:

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$ ls -l /usr/bin/cal
lrwxrwxrwx 1 root root 4 Oct 28  2014 /usr/bin/cal -> ncal

[lerner]

So please indulge my stupid question to why does cal -M not work, but ncal -M does?

[Paeryn]

So please indulge my stupid question to why does cal -M not work, but ncal -M does?

cal -M doesn't work because that isn't a valid option for cal.

Probably ncal started out as a separate program with its separate options, then the two programs merged. Either that or when they wanted to update it they wanted to change the options so for backwards compatability the old behaviour was retained if called as cal. Or something.

When the actual cal program gets run it checks what name was used to run it so that it can respond and behave appropriately.

[mfa298]

So please indulge my stupid question to why does cal -M not work, but ncal -M does?

Often these tool have been around in the *nix world for decades. This may mean there's no desire to change how the original program worked as that has the potential to break a lot of things.