This is another short blog post. Since I have migrated to debian from arch linux I had some minor problems. The most annoying problem for, as a german, was that the cal command had the first weekday set to sunday... IMO that should be easy to fix. Haha... This is what I tried:

Set the environment variable LC_TIME to something like de_DE.UTF-8. The month names became german, but the first weekday did not change.
I studied the manpage and discovered the flag -M. I got an exit code 64 and the help page of the cal tool. WTF?!?!.
I studied the manpage locale and also read some cross referenced manpages, since I had the opinion that my environment variables are wrong. No solution found...
Coincidentally, I realized, that there are two commands!! There also is ncal, which is mentioned in the SYNOPSIS section of the cal manpage. I have no idea why this command is there. It does almost the same and it correctly interprets LC_TIME. The only thing to remember is to supply the -b flag in order to generate the same output as cal. I have set an alias in my fish config like this:

alias cal="ncal -b"

Now my calendars render correctly again! No idea why such an oddysee was necessary… Here is the result:

$ env LC_TIME=de_DE.UTF-8 /usr/bin/cal
     März 2017
So Mo Di Mi Do 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 31

$ env LC_TIME=de_DE.UTF-8 /usr/bin/ncal -b
     März 2017
Mo Di Mi Do Fr Sa So
       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 31

Really annoying...