false: 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/false - from package: coreutils

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

On Debian possible default full paths are:

/bin/false - from package: coreutils
/usr/lib/klibc/bin/false - from package: klibc-utils
/usr/lib/wims/bin/false - from package: wims

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

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