exrchr: 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 Debian possible default full paths are:

/usr/bin/exrchr - from package: exrtools

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

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