rmhist: 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/rmhist - from package: atfs

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

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