tpm_selftest: 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:

/usr/sbin/tpm_selftest - from package: tpm-tools

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

On Debian possible default full paths are:

/usr/sbin/tpm_selftest - from package: tpm-tools

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

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