in.rshd: command not found

Have You tried accessing the binary with the full path?

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/sbin/in.rshd - from package: rsh-server

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

On Debian possible default full paths are:

/usr/sbin/in.rshd - from package: rsh-redone-server
/usr/sbin/in.rshd - from package: rsh-server

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