To work with Russian letters, you need the usual Russification of the computer, through which you work with the Linux cluster.
Machines with Windows, as a rule, have the necessary means of Russification, and they are usually already installed (if you work in Russia).
In addition, you need to configure the putty program to convert koi8-r to
cp-1251 for the screen and backward for the keyboard.
On a Unix/Linux machine, you need to install the Cronyx (Cyrillic) fonts in XFree86, which are present in all the latest Linux distributions, and configure “XkbLayout” – “us, ru” (for XFree86 4.x).
After configuring your workstation, you can go to the Linux cluster (by ssh)
and set the LANG environment variable to ru_RU.KOI8-R:

LANG = en_RU.KOI8-R; Export LANG – for sh and bash
Setenv LANG KOI8 – for csh / tcsh

After that, when working with vi/vim, mc and netscape/mozilla,
Russian letters will be displayed, and thus some programs (for example, mc) are Russified.
To Russify the program for working with pine email, additional settings for this program are required. Run it and perform the following manipulations:

Pine
S
C

Then scroll the list of settings to character-set and press:
<Enter>
KOI8-R
<Enter>
E
Y
Q

You can enter the definition of LANG variable “forever” by writing a string with its definition into a .bashrc (sh/bash) file, or in .cshrc (csh/tsch) in your home directory. But in this case you will have difficulties when working on a Linux cluster from non-Russified workstations, for example, from abroad.