rm: 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:

/bin/rm - from package: coreutils

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

On Debian possible default full paths are:

/bin/rm - from package: coreutils
/usr/bin/rm - from package: safe-rm

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

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