telegram-cli: 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/telegram-cli - from package: telegram-cli

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

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