psiphi: 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/psiphi - from package: emboss

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

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