viwsl: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/viwsl - from package: wsl

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/viwsl - from package: wsl

You may install the required package with command apt-get install {package}

Error in other languages:
viwsl: bevel nie gevind nie
viwsl: comandă negăsită
viwsl: comando não encontrado
viwsl: commande introuvable
viwsl: command not found
viwsl: käsku ei ole
viwsl: không tìm thấy lệnh
viwsl: komanda nerasta
viwsl: Kommando nicht gefunden.
viwsl: kommandot finns inte
viwsl: komut yok
viwsl: nie znaleziono polecenia
viwsl: níor aimsíodh an t-ordú
viwsl: no se encontró la orden
viwsl: no s'ha trobat l'ordre
viwsl: opdracht niet gevonden
viwsl: parancs nem található
viwsl: perintah tidak ditemukan
viwsl: príkaz nenájdený
viwsl: příkaz nenalezen
viwsl: команда не найдена
viwsl: командата не е открита
viwsl: 命令找不到
viwsl: コマンドが見つかりません