Unable to have normal letters


Dear community!
I`ve recently faced this problem

how to fix that?


That’s odd. I would say try a different browser, or restart the workspace, or restart the computer. Hope it helps.


When printing binary data to the terminal (e.g. cat or curl an image), often there will be random characters that will put terminal into alternate character set mode

Usually running tput rmacs or echo -e "\x0f \x1b(B \x1b)0" should restore it see http://superuser.com/a/196376/209752

If you are interested in more details see http://www.in-ulm.de/~mascheck/various/alternate_charset/

It’s all about both switching between several ‘character sets’ and ‘translation tables’ as well.
The following paragraph from the VT100 Manual:

The appropriate G0 and G1 character sets are designated from one of the
five possible character sets. The G0 and G1 sets are invoked by the
codes SI and SO (shift in and shift out) respectively.  

(Note: this page is concerning all the VT100 alike terminals, emulations and related emulators like xterm(1) or dtterm(1), but not hpterm(1) in contrast.)

So, in general, there are two different “modes”, initially G0 is the current one. “shift in” (Ctrl-N) causes G1 to become current, “shift out” (Ctrl-O) causes G0 to become current. These variables G0 and G1 each point at a translation table. The most recommended echoing of Ctrl-O will only make G0 current, but there is no guarantee that G0 points at the right translation table. But this is done with the following:

G0 Sets Sequence   G1 Sets Sequence   Meaning
 ESC ( A            ESC ) A            United Kingdom Set
 ESC ( B            ESC ) B            ASCII Set
 ESC ( 0            ESC ) 0            Special Graphics
 ESC ( 1            ESC ) 1            Alternate Character ROM Standard Character Set
 ESC ( 2            ESC ) 2            Alternate Character ROM Special Graphic