Short version: hyphen '-' 0x2d is good, dle '‐' 0x90 is bad on shell command lines.
Longer version:
The other day I tried to connect my trusty old Acer Travelmate running alpine linux to my access point. And since I don't do this often, I had to check the man pages. (Note: I do this by hand, calling ip, iwconfig, wpa_supplicant on the shell.) Open the man page, "man wpa_supplicant", search for the EXAMPLES section, copy the relevant line, possibly edit the name of the network interface ... and go:
wpa_supplicant ‐Dnl80211,wext ‐c/etc/wpa_supplicant.conf ‐iwlan0 # BROKEN!
except that this did not work. It told me the --help output without any excuse and returned 255 as return code.
It took me some head scratching, and eventually by documenting what I did into emacs, emacs surprisingly added some unexpected color to this commandline above. The hyphens (or dashes?) introducing the options (or switches?) on the command line were all colored red (not white). This provided the first clue of what was really going on. My good old friend "od -tx1a" would tell me:
$ echo -n '...t ‐Dnl80211' | od -tx1a
0000000 2e 2e 2e 74 20 e2 80 90 44 6e 6c 38 30 32 31 31
. . . t sp b nul dle D n l 8 0 2 1 1
0000020
$ ascii '-'
ASCII 2/13 is decimal 045, hex 2d, octal 055, bits 00101101: prints as `-'
Official name: Hyphen
Other names: Dash, Minus, Worm
So, the examples in the man page are broken, because somehow short hyphens (those to indicate breaks in a word at the end of a line, if I'm not mistaken) got into there. Interestingly, the output of "wpa_supplicant --help" features an example (last line), which is corrct. The problem does not exist on Debian.
So just in case you get bitten by this ...